Use a Github app to push in update-dependencies

App is already installed on the repo, and is here: https://github.com/apps/cibuildwheel-bot

.github/workflows/update-dependencies.yml

@@ -11,17 +11,30 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    
     - uses: actions/setup-python@v2
       name: Install Python 3.9
       with:
         python-version: 3.9
         architecture: x64
+    
     - name: Install dependencies
       run: python -m pip install ".[dev]"
+    
     - name: "Run update: dependencies"
       run: python ./bin/update_dependencies.py
+    
     - name: "Run update: python configs"
       run: python ./bin/update_pythons.py --force
+    
+    # we use this step to grab a Github App auth token, so that PRs generated by this workflow
+    # run the GHA tests.
+    - uses: tibdex/github-app-token@v1
+      id: generate-token
+      with:
+        app_id: ${{ secrets.CIBUILDWHEEL_BOT_APP_ID }}
+        private_key: ${{ secrets.CIBUILDWHEEL_BOT_APP_PRIVATE_KEY }}
+    
     - name: Create Pull Request
       if: github.ref == 'refs/heads/master' && github.repository == 'joerick/cibuildwheel'
       uses: peter-evans/create-pull-request@v3
@@ -33,4 +46,5 @@ jobs:
 
           PR generated by "Update dependencies" [workflow](https://github.com/${{github.repository}}/actions/runs/${{github.run_id}}).
         branch: update-dependencies-pr
+        token: ${{ steps.generate-token.outputs.token }}
         delete-branch: true