Corrected rule cap2m.8, as it implies that stacked MiM caps may not
overlap contacts---which essentially makes them not able to stack. . .

sky130/magic/sky130.tech

diff --git a/sky130/magic/sky130.tech b/sky130/magic/sky130.tech
index af52099..5cf453d 100644
--- a/sky130/magic/sky130.tech
+++ b/sky130/magic/sky130.tech
@@ -5754,7 +5754,7 @@
 
  surround *mimcap2 *metal4/m4 140 absence_illegal \
 	"Metal4 must surround MiM2 cap by %d (cap2m.3)"
- spacing via3 *mimcap2 80 touching_illegal \
+ spacing via3,mimcc *mimcap2 80 touching_illegal \
 	"MiM2 cap spacing to via3 < %d (cap2m.8 - via3.4)"
  spacing *mimcap2 *metal4/m4 500 surround_ok \
 	"MiM2 cap spacing to unrelated metal4 < %d (cap2m.11)"