Have SyncAction create PRs

GH Action could run hourly (update cron)
Using the same SyncAction.jar (update SyncDate var)
Instead of Commit/Push steps, create var of changed_files and create PR per file (i.e., per GPML)

Here are some code suggestions from ChatGPT:

- name: Find changed files
  run: |
    CHANGED_FILES=$(git diff --name-only)
    echo "::set-env name=CHANGED_FILES::$CHANGED_FILES"

- name: Create pull requests with:
  env:
    github_token: ${{ secrets.PICOPAT}}
  run: |
    for file in $CHANGED_FILES; do
     filename=$(basename $file)
     git checkout -b "pending-approval-$filename"
         git add $file
     git commit -m 'Test for PR'
     git push -u origin "pending-approval-$filename"
        gh pr create --title "Automatically created pull request for $filename" --template .github/PR_TEMPLATE/gpml-change.yml --base main --head "pending-approval-$filename" || true
     git checkout main
done

Need to add token to checkout in order for these PRs to trigger downstream actions (like tests and automerge):
```
with:
persist-credentials: false
token: ${{ secrets.PICOPAT }}
```

wikipathways / wikipathways-development

Have SyncAction create PRs #124