Bumps [actions/labeler](https://github.com/actions/labeler) from 3 to 4. - [Release notes](https://github.com/actions/labeler/releases) - [Commits](https://github.com/actions/labeler/compare/v3...v4)
opened, synchronize, reopened are the defaults for `pull_request_target`, `edited` will trigger the label action if the PRs base branch is changed.