Github Actions triggered by pushes are not detected as pull requests

[judson-firebolt]

I am trying to use reviewdog/action-golangci-lint@v2, triggering on my PR when I push changes to the branch. However, reviewdog reports reviewdog: this is not PullRequest build.

I looked at the code in getBuildInfoFromGitHubActionEventPath, which is getting the event JSON object from a file. It expects the json to have a field pull_request, otherwise it returns that this is not a PR. I have verified the field pull_request does not exist when the workflow is triggered by me pushing to the branch.

This seems like a bug.

Also, it seems like folks have hit this in various contexts: actions/checkout#58