Bump pygithub from 1.52 to 1.53

Bumps [pygithub](https://github.com/PyGithub/PyGithub) from 1.52 to 1.53.
- [Release notes](https://github.com/PyGithub/PyGithub/releases)
- [Commits](PyGithub/PyGithub@v1.52...v1.53)

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

Author: dependabot-preview[bot]

dev-requirements.txt

@@ -19,7 +19,7 @@ mypy==0.782  # Type checking
 pip_check_reqs==2.1.1
 pydocstyle==5.0.2  # Lint docstrings
 pyenchant==3.1.1  # Bindings for a spellchecking sytem
-pygithub==1.52
+pygithub==1.53
 pylint==2.5.3  # Lint
 pyroma==2.6  # Packaging best practices checker
 pytest-cov==2.10.1  # Measure code coverage