Added support in the magic tech file for ESD devices of the 5V nFET
and pFET varieties.  These are essentially just standard 5V FETs with
a marker layer used for LVS purposes;  however, as these are the devices
with angled gates, they can be used to suppress DRC errors in the
device layouts (which has not yet been done).

sky130/magic/sky130.tech

diff --git a/sky130/magic/sky130.tech b/sky130/magic/sky130.tech
index 97cf5a4..72ba8f7 100644
--- a/sky130/magic/sky130.tech
+++ b/sky130/magic/sky130.tech
@@ -889,6 +889,16 @@
 	calma 81 4
 
 #----------------------------------------------------------------
+# ESDID is a marker layer for ESD devices in the padframe I/O.
+#----------------------------------------------------------------
+
+ layer ESDID  
+	bloat-all mvnfetesd *mvndiff,*poly
+	bloat-all mvpfetesd *mvpdiff,*poly
+	grow 100
+	calma 81 19
+
+#----------------------------------------------------------------
 # NPNID and PNPID apply to bipolar transistors
 #----------------------------------------------------------------