• https://github.blog/2020-08-03-github-actions-improvements-for-fork-and-pull-request-workflows/
• https://docs.github.com/en/actions/reference/events-that-trigger-workflows#workflow_run

Since workflow_run have read/write permission even for pull requests from fork repo, we can run diagnostic tools results on pull_request event, save them as artifacts, and use the artifacts from workflow_run event to post results back to Pull Requests.