Bump pygit2 from 1.15.1 to 1.16.0

Bumps [pygit2](https://github.com/libgit2/pygit2) from 1.15.1 to 1.16.0.
- [Changelog](https://github.com/libgit2/pygit2/blob/master/CHANGELOG.md)
- [Commits](libgit2/pygit2@v1.15.1...v1.16.0)

---
updated-dependencies:
- dependency-name: pygit2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>