Action fails when PR is submitted from a fork

[per1234]

When a PR is submitted from a fork, the GitHub access token provided by ${{ secrets.GITHUB_TOKEN}} is downgraded to read-only. This causes the attempt to label the PR to fail:

Resource not accessible by integration

This has been discussed at actions/labeler#12.

The only workaround I've found is running the action from a scheduled workflow, as they started out to do in the actions/labeler action (actions/labeler@375fca6). However, as they realized, it's not so simple as just changing a couple lines in the workflow configuration. The action code likely needs significant reworking as well. I managed to get this working in an action that comments on PRs.

If you don't want to rework the action, the next best thing would be to document the limitation in the readme. Even if the action is limited to labeling issues, that's still very useful.