Updates the requirements on [actions/checkout](https://github.com/actions/checkout) to permit the latest version.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/master/CHANGELOG.md)
- [Commits](28c7f3d2b5)
Signed-off-by: dependabot[bot] <support@github.com>