Don't run zip workflow on markdown changes. (#4818)

Author: ryanwilson

.github/workflows/zip.yml

@@ -5,6 +5,8 @@ on:
     paths:
     - 'ZipBuilder/**'
     - '.github/workflows/zip.yml'
+    # Don't run based on any markdown only changes.
+    - '!ZipBuilder/**/*.md'
   schedule:
     # Run every day at midnight(PST) - cron uses UTC times
     - cron:  '0 8 * * *'