fix: explicitly add Formula and metadata to PR

- Add add-paths parameter to create-pull-request action
- Ensures Formula/eengine.rb and formula-metadata.json are included in PR
- Fixes issue where PR only contained metadata

Author: ronaldtse

.github/workflows/update-formula.yml

@@ -35,6 +35,9 @@ jobs:
         uses: peter-evans/create-pull-request@v5
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
+          add-paths: |
+            Formula/eengine.rb
+            formula-metadata.json
           commit-message: "chore: update eengine to ${{ github.event.client_payload.version || inputs.version }}"
           title: "Update eengine formula"
           body: |