Update pygithub requirement in /requirements

Updates the requirements on [pygithub](https://github.com/pygithub/pygithub) to permit the latest version.
- [Release notes](https://github.com/pygithub/pygithub/releases)
- [Changelog](https://github.com/PyGithub/PyGithub/blob/main/doc/changes.rst)
- [Commits](PyGithub/PyGithub@v1.54...v2.3.0)

---
updated-dependencies:
- dependency-name: pygithub
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

requirements/base.txt

@@ -2,7 +2,7 @@
 # -----------------------
 
 GitPython>=3.1,<3.2
-PyGithub>=1.54,<2.3
+PyGithub>=1.54,<2.4
 PyQt5>=5.15,<5.16
 pyqt5ac>=1.2,<1.3
 python-slugify>=4.0,<8.1