Address authentication issue release branch update

[rvermeulen]

Updating a release branch may involve updating GitHub Action workflow file. Updating a GitHub Action workflow file requires additional permission that we cannot assign to the workflow provided token.

To address this, we use a GitHub app with a scoped token to update the release branch.

Merge / deployment checklist

• Confirm this change is backwards compatible with existing workflows.
• Confirm the readme has been updated if necessary.
• Confirm the changelog has been updated if necessary.