Replaced an accidentally-deleted line from the sky130 Makefile that
prevents the base I/O verilog macros from being included into the
I/O verilog library.

sky130/Makefile.in

diff --git a/sky130/Makefile.in b/sky130/Makefile.in
index c8e19c9..b62fa54 100644
--- a/sky130/Makefile.in
+++ b/sky130/Makefile.in
@@ -1025,6 +1025,7 @@
 		-gds %l/latest/cells/*/*.gds compile-only \
 			sort=../common/sort_pdkfiles.py \
 			options=custom/scripts/sky130_fd_io_import.tcl \
+		-verilog %l/latest/cells/*/*.*.v \
 		-verilog %l/latest/cells/*/*.v exclude=*.*.v,sky130_ef_io.v \
 			compile-only filter=custom/scripts/inc_verilog.py \
 			sort=../common/sort_pdkfiles.py \