Bump gitpython from 2.1.15 to 3.1.30

Bumps [gitpython](https://github.com/gitpython-developers/GitPython) from 2.1.15 to 3.1.30.
- [Release notes](https://github.com/gitpython-developers/GitPython/releases)
- [Changelog](https://github.com/gitpython-developers/GitPython/blob/main/CHANGES)
- [Commits](gitpython-developers/GitPython@2.1.15...3.1.30)

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

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

requirements.txt

@@ -20,7 +20,7 @@ dicttoxml==1.7.4
 
 # fails on requiring newer version of setuptools
 #Flask==0.10.1
-GitPython==2.1.15
+GitPython==3.1.30
 
 # this GCP API is surprisingly awful, not using
 #google-api-python-client==1.11.0