chore(deps): bump pygithub in /.github/workflows/update-tests

Bumps [pygithub](https://github.com/pygithub/pygithub) from 1.58.0 to 1.59.1.
- [Release notes](https://github.com/pygithub/pygithub/releases)
- [Changelog](https://github.com/PyGithub/PyGithub/blob/v1.59.1/doc/changes.rst)
- [Commits](PyGithub/PyGithub@v1.58.0...v1.59.1)

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

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

.github/workflows/update-tests/requirements.txt

@@ -1 +1 @@
-PyGithub==1.58.0
+PyGithub==1.59.1