Add validation of version string to pre-commit hook

Author: morgen-peschke

.githooks/pre-commit

@@ -31,6 +31,16 @@ EOF
 exit 1
 fi
 
+if mill show __.publishVersion 2>/dev/null | jq --raw-output '.[]' | \grep -E '[^0-9.]'
+then
+ cat <<\EOF
+Error: Version number contains unexpected characters.
+
+Sometimes a 'g' will sneak in there, (see version 0.2g.0), please double-check the publishVersion in build.sc
+EOF
+ exit 1
+fi
+
 mill __.compile + \
  __.test + \
  __.fix --check + \