Build(deps): Bump knplabs/github-api from 3.14.1 to 3.15.0 (#2835)

Bumps [knplabs/github-api](https://github.com/KnpLabs/php-github-api) from 3.14.1 to 3.15.0.
- [Release notes](https://github.com/KnpLabs/php-github-api/releases)
- [Changelog](https://github.com/KnpLabs/php-github-api/blob/master/CHANGELOG-3.X.md)
- [Commits](KnpLabs/php-github-api@v3.14.1...v3.15.0)

---
updated-dependencies:
- dependency-name: knplabs/github-api
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>