Use manylinux-bot for dependency updates

Author: mayeut

.github/workflows/update-dependencies.yml

@@ -17,6 +17,13 @@ jobs:
     - uses: excitedleigh/setup-nox@v2.0.0
     - name: "Run update: dependencies"
       run: nox --force-color
+    # 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.MANYLINUX_BOT_APP_ID }}
+        private_key: ${{ secrets.MANYLINUX_BOT_APP_PRIVATE_KEY }}
     - name: Create Pull Request
       if: github.ref == 'refs/heads/master' && github.repository == 'pypa/manylinux'
       uses: peter-evans/create-pull-request@v3
@@ -28,4 +35,5 @@ 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