Corrected a comment line in the Makefile to match the text of the
option in configure.
diff --git a/sky130/Makefile.in b/sky130/Makefile.in
index 2461f76..24c1672 100644
--- a/sky130/Makefile.in
+++ b/sky130/Makefile.in
@@ -14,7 +14,7 @@
# Run "configure" from the top level directory. Use the following
# configuration options to match your environment:
#
-# --enable-skywater-pdk[=<path>]
+# --enable-sky130-pdk[=<path>]
# If enabled, install the skywater PDK. If <path> is specified,
# then the skywater PDK is expected to be found rooted at the
# given path. If not specified, then the skywater PDK will be
