Update repo-sync.yml

Author: markzegarelli

.github/workflows/repo-sync.yml

@@ -22,4 +22,7 @@ jobs:
       with:
         source_branch: ${{ secrets.INTERMEDIATE_BRANCH }}
         destination_branch: master
+        pr_title: 'repo sync'
+        pr_body: "This is an automated pull request to sync changes between the public and private repos.\n\n:robot: This pull request should be merged (not squashed) to preserve continuity across repos, so please let a bot do the merging!"
+        pr_label: autoupdate,automated-reposync-pr
         github_token: ${{ secrets.GITHUB_TOKEN }}