Quotes around cron string in pythonpackage.yml

Probably needed to avoid problems due to YAML interpreting special characters.

Co-authored-by: Timothy <75321887+timothy-nunn@users.noreply.github.com>

Author: johnomotani

.github/workflows/pythonpackage.yml

@@ -7,7 +7,7 @@ on:
   push:
   pull_request:
   schedule:
-    - cron: 25 1 3 * *
+    - cron: '25 1 3 * *'
 
 concurrency:
   group: ${{ github.workflow}}-${{ github.ref }}