sky130_ef_io*.lib: operating_conditions() use a quoted-string everywhere

Add surrounding quotemarks (example):
  operating_conditions (Max) {
Transformed into:
  operating_conditions ("Max") {

Liberty_Reference_Manual_R-2020-09.pdf page 72 describes the group type as
 'name-string' as opposed to 'name-id'.
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ff_n40C_1v95_5v50.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ff_n40C_1v95_5v50.lib
index 80cc4b3..dcbe154 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ff_n40C_1v95_5v50.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ff_n40C_1v95_5v50.lib
@@ -76,7 +76,7 @@
   
   voltage_map(VSSD1, 0.00);
 
-  operating_conditions (Min) {
+  operating_conditions ("Min") {
     process	: 1 ;
     temperature : -40	;
     voltage	: 1.95	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v40_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v40_1v65.lib
index fe7dfa0..9b0fff1 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v40_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v40_1v65.lib
@@ -76,7 +76,7 @@
   
   voltage_map(VSSD1, 0.00);
 
-  operating_conditions (deep_sleep_max_100) {
+  operating_conditions ("deep_sleep_max_100") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.40	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v60_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v60_1v65.lib
index 95c38f5..9d7a825 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v60_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v60_1v65.lib
@@ -76,7 +76,7 @@
   
   voltage_map(VSSD1, 0.00);
 
-  operating_conditions (max_ind) {
+  operating_conditions ("max_ind") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.60	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v60_3v00.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v60_3v00.lib
index 6ed9a47..7708bf4 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v60_3v00.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v60_3v00.lib
@@ -76,7 +76,7 @@
   
   voltage_map(VSSD1, 0.00);
 
-  operating_conditions (max_io_ind) {
+  operating_conditions ("max_io_ind") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.60	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_n40C_1v60_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_n40C_1v60_1v65.lib
index 9d4a4de..d545eb2 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_n40C_1v60_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_n40C_1v60_1v65.lib
@@ -76,7 +76,7 @@
   
   voltage_map(VSSD1, 0.00);
 
-  operating_conditions (Max) {
+  operating_conditions ("Max") {
     process	: 1 ;
     temperature : -40	;
     voltage	: 1.60	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_tt_025C_1v80_3v30.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_tt_025C_1v80_3v30.lib
index da811b2..39429e7 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_tt_025C_1v80_3v30.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_tt_025C_1v80_3v30.lib
@@ -76,7 +76,7 @@
   
   voltage_map(VSSD1, 0.00);
 
-  operating_conditions (Typ) {
+  operating_conditions ("Typ") {
     process	: 1 ;
     temperature : 025	;
     voltage	: 1.80	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_tt_100C_1v80_3v30.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_tt_100C_1v80_3v30.lib
index abc873e..1cfe12e 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_tt_100C_1v80_3v30.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_tt_100C_1v80_3v30.lib
@@ -76,7 +76,7 @@
   
   voltage_map(VSSD1, 0.00);
 
-  operating_conditions (typ_ind) {
+  operating_conditions ("typ_ind") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.80	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ff_n40C_1v95_5v50.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ff_n40C_1v95_5v50.lib
index cab2013..2e3a598 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ff_n40C_1v95_5v50.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ff_n40C_1v95_5v50.lib
@@ -74,7 +74,7 @@
 
   
 
-  operating_conditions (Min) {
+  operating_conditions ("Min") {
     process	: 1 ;
     temperature : -40	;
     voltage	: 1.95	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v40_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v40_1v65.lib
index 2dfdcd0..054ec9e 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v40_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v40_1v65.lib
@@ -74,7 +74,7 @@
 
   
 
-  operating_conditions (deep_sleep_max_100) {
+  operating_conditions ("deep_sleep_max_100") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.40	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v60_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v60_1v65.lib
index 8ae2bc4..548e7e2 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v60_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v60_1v65.lib
@@ -74,7 +74,7 @@
 
   
 
-  operating_conditions (max_ind) {
+  operating_conditions ("max_ind") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.60	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v60_3v00.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v60_3v00.lib
index 008a2cd..0f9e351 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v60_3v00.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v60_3v00.lib
@@ -74,7 +74,7 @@
 
   
 
-  operating_conditions (max_io_ind) {
+  operating_conditions ("max_io_ind") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.60	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_n40C_1v60_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_n40C_1v60_1v65.lib
index e158eb4..3773ff6 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_n40C_1v60_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_n40C_1v60_1v65.lib
@@ -74,7 +74,7 @@
 
   
 
-  operating_conditions (Max) {
+  operating_conditions ("Max") {
     process	: 1 ;
     temperature : -40	;
     voltage	: 1.60	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_tt_025C_1v80_3v30.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_tt_025C_1v80_3v30.lib
index 678593c..fa08e08 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_tt_025C_1v80_3v30.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_tt_025C_1v80_3v30.lib
@@ -74,7 +74,7 @@
 
   
 
-  operating_conditions (Typ) {
+  operating_conditions ("Typ") {
     process	: 1 ;
     temperature : 025	;
     voltage	: 1.80	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_tt_100C_1v80_3v30.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_tt_100C_1v80_3v30.lib
index 6d20e15..46489db 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_tt_100C_1v80_3v30.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_tt_100C_1v80_3v30.lib
@@ -74,7 +74,7 @@
 
   
 
-  operating_conditions (typ_ind) {
+  operating_conditions ("typ_ind") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.80	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ff_n40C_1v95_5v50.lib b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ff_n40C_1v95_5v50.lib
index 231821a..48e2b28 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ff_n40C_1v95_5v50.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ff_n40C_1v95_5v50.lib
@@ -81,7 +81,7 @@
   voltage_map(BDY2_B2B, 0.00);
   voltage_map(G_CORE, 0.00);
 
-  operating_conditions (Min) {
+  operating_conditions ("Min") {
     process	: 1 ;
     temperature : -40	;
     voltage	: 1.95	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v40_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v40_1v65.lib
index fbfef52..a61d911 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v40_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v40_1v65.lib
@@ -81,7 +81,7 @@
   voltage_map(BDY2_B2B, 0.00);
   voltage_map(G_CORE, 0.00);
 
-  operating_conditions (deep_sleep_max_100) {
+  operating_conditions ("deep_sleep_max_100") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.40	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v60_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v60_1v65.lib
index ad252bb..deffa60 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v60_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v60_1v65.lib
@@ -81,7 +81,7 @@
   voltage_map(BDY2_B2B, 0.00);
   voltage_map(G_CORE, 0.00);
 
-  operating_conditions (max_ind) {
+  operating_conditions ("max_ind") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.60	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v60_3v00.lib b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v60_3v00.lib
index 4bafaa3..dccc7b0 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v60_3v00.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v60_3v00.lib
@@ -81,7 +81,7 @@
   voltage_map(BDY2_B2B, 0.00);
   voltage_map(G_CORE, 0.00);
 
-  operating_conditions (max_io_ind) {
+  operating_conditions ("max_io_ind") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.60	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_n40C_1v60_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_n40C_1v60_1v65.lib
index 03c6324..470e191 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_n40C_1v60_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_n40C_1v60_1v65.lib
@@ -81,7 +81,7 @@
   voltage_map(BDY2_B2B, 0.00);
   voltage_map(G_CORE, 0.00);
 
-  operating_conditions (Max) {
+  operating_conditions ("Max") {
     process	: 1 ;
     temperature : -40	;
     voltage	: 1.60	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_tt_025C_1v80_3v30.lib b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_tt_025C_1v80_3v30.lib
index 0b67ea9..7d54b9b 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_tt_025C_1v80_3v30.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_tt_025C_1v80_3v30.lib
@@ -81,7 +81,7 @@
   voltage_map(BDY2_B2B, 0.00);
   voltage_map(G_CORE, 0.00);
 
-  operating_conditions (Typ) {
+  operating_conditions ("Typ") {
     process	: 1 ;
     temperature : 025	;
     voltage	: 1.80	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_tt_100C_1v80_3v30.lib b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_tt_100C_1v80_3v30.lib
index 4aca243..bccc761 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_tt_100C_1v80_3v30.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_tt_100C_1v80_3v30.lib
@@ -81,7 +81,7 @@
   voltage_map(BDY2_B2B, 0.00);
   voltage_map(G_CORE, 0.00);
 
-  operating_conditions (typ_ind) {
+  operating_conditions ("typ_ind") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.80	;