Modified cifinput section of the magic tech file to always draw
type "pwell" in deep n-well P regions;  otherwise isolated bulk
nFET devices are not extracted correctly.

sky130/magic/sky130.tech

diff --git a/sky130/magic/sky130.tech b/sky130/magic/sky130.tech
index 570b509..2d9527c 100644
--- a/sky130/magic/sky130.tech
+++ b/sky130/magic/sky130.tech
@@ -2286,6 +2286,11 @@
  layer pwell TAP
  and-not NWELL
 
+ # Always draw pwell in deep-nwell P-regions
+ layer pwell DNWELL
+ and-not NWELL
+ and-not NPNID
+
  layer dnwell DNWELL
  labels DNWELL