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

Add surrounding quotemarks (example):
  operating_conditions (deep_sleep_lfclk_max_-40) {
Transformed into:
  operating_conditions ("deep_sleep_lfclk_max_-40") {

The use of the minus character in something that would otherwise look like an
identifer might be problematic for some parsers.  Everything should be happy
if it was quoted as the specification allows.

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_ss_100C_1v45_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v45_1v65.lib
index 5664f11..5666bb9 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v45_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_100C_1v45_1v65.lib
@@ -76,7 +76,7 @@
   
   voltage_map(VSSD1, 0.00);
 
-  operating_conditions (deep_sleep_lfclk_max_-40) {
+  operating_conditions ("deep_sleep_lfclk_max_-40") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.45	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_n40C_1v40_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_n40C_1v40_1v65.lib
index acd1272..4cf4c20 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_n40C_1v40_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_n40C_1v40_1v65.lib
@@ -76,7 +76,7 @@
   
   voltage_map(VSSD1, 0.00);
 
-  operating_conditions (deep_sleep_max_-40) {
+  operating_conditions ("deep_sleep_max_-40") {
     process	: 1 ;
     temperature : -40	;
     voltage	: 1.40	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_n40C_1v45_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_n40C_1v45_1v65.lib
index 298c4c0..cb7bf31 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_n40C_1v45_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped3_pad_ss_n40C_1v45_1v65.lib
@@ -76,7 +76,7 @@
   
   voltage_map(VSSD1, 0.00);
 
-  operating_conditions (deep_sleep_lfclk_max_-40) {
+  operating_conditions ("deep_sleep_lfclk_max_-40") {
     process	: 1 ;
     temperature : -40	;
     voltage	: 1.45	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v45_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v45_1v65.lib
index 947dbf6..063541f 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v45_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_100C_1v45_1v65.lib
@@ -74,7 +74,7 @@
 
   
 
-  operating_conditions (deep_sleep_lfclk_max_-40) {
+  operating_conditions ("deep_sleep_lfclk_max_-40") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.45	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_n40C_1v40_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_n40C_1v40_1v65.lib
index 6a23a49..58e88dc 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_n40C_1v40_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_n40C_1v40_1v65.lib
@@ -74,7 +74,7 @@
 
   
 
-  operating_conditions (deep_sleep_max_-40) {
+  operating_conditions ("deep_sleep_max_-40") {
     process	: 1 ;
     temperature : -40	;
     voltage	: 1.40	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_n40C_1v45_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_n40C_1v45_1v65.lib
index 3c44dfb..65b427b 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_n40C_1v45_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_ef_io__vssd_lvc_clamped_pad_ss_n40C_1v45_1v65.lib
@@ -74,7 +74,7 @@
 
   
 
-  operating_conditions (deep_sleep_lfclk_max_-40) {
+  operating_conditions ("deep_sleep_lfclk_max_-40") {
     process	: 1 ;
     temperature : -40	;
     voltage	: 1.45	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v45_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v45_1v65.lib
index 061bcc0..cfde4b0 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v45_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_100C_1v45_1v65.lib
@@ -81,7 +81,7 @@
   voltage_map(BDY2_B2B, 0.00);
   voltage_map(G_CORE, 0.00);
 
-  operating_conditions (deep_sleep_lfclk_max_-40) {
+  operating_conditions ("deep_sleep_lfclk_max_-40") {
     process	: 1 ;
     temperature : 100	;
     voltage	: 1.45	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_n40C_1v40_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_n40C_1v40_1v65.lib
index 84bbf90..26b699c 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_n40C_1v40_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_n40C_1v40_1v65.lib
@@ -81,7 +81,7 @@
   voltage_map(BDY2_B2B, 0.00);
   voltage_map(G_CORE, 0.00);
 
-  operating_conditions (deep_sleep_max_-40) {
+  operating_conditions ("deep_sleep_max_-40") {
     process	: 1 ;
     temperature : -40	;
     voltage	: 1.40	;
diff --git a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_n40C_1v45_1v65.lib b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_n40C_1v45_1v65.lib
index b61c21d..e7ce641 100644
--- a/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_n40C_1v45_1v65.lib
+++ b/sky130/custom/sky130_fd_io/lib/sky130_fd_io__top_ground_lvc_wpad_ss_n40C_1v45_1v65.lib
@@ -81,7 +81,7 @@
   voltage_map(BDY2_B2B, 0.00);
   voltage_map(G_CORE, 0.00);
 
-  operating_conditions (deep_sleep_lfclk_max_-40) {
+  operating_conditions ("deep_sleep_lfclk_max_-40") {
     process	: 1 ;
     temperature : -40	;
     voltage	: 1.45	;