build(deps): bump jupyterlab-git from 0.44.0 to 0.50.0 in /docker/py

Bumps [jupyterlab-git](https://github.com/jupyterlab/jupyterlab-git) from 0.44.0 to 0.50.0.
- [Release notes](https://github.com/jupyterlab/jupyterlab-git/releases)
- [Changelog](https://github.com/jupyterlab/jupyterlab-git/blob/main/CHANGELOG.md)
- [Commits](jupyterlab/jupyterlab-git@v0.44.0...v0.50.0)

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

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

docker/py/requirements.txt

@@ -2,7 +2,7 @@ bleach>5.0.0 # closes #300
 certifi>=2022.12.7 # not directly required, pinned by Snyk to avoid a vulnerability
 Jinja2<3.1 # because of https://github.com/jupyter/nbconvert/issues/1742
 jupyter-server-proxy==4.1.0
-jupyterlab-git==0.44.0
+jupyterlab-git==0.50.0
 jupyterlab-system-monitor~=0.8.0
 mistune>=2.0.1 # not directly required, pinned by Snyk to avoid a vulnerability
 papermill~=2.5.0