Bump python-gitlab from 6.2.0 to 6.4.0

Bumps [python-gitlab](https://github.com/python-gitlab/python-gitlab) from 6.2.0 to 6.4.0.
- [Release notes](https://github.com/python-gitlab/python-gitlab/releases)
- [Changelog](https://github.com/python-gitlab/python-gitlab/blob/main/CHANGELOG.md)
- [Commits](python-gitlab/python-gitlab@v6.2.0...v6.4.0)

---
updated-dependencies:
- dependency-name: python-gitlab
  dependency-version: 6.4.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements.txt

@@ -2,7 +2,7 @@ docopt-ng==0.9.0
 Flask==3.1.0
 Flask-Cors==6.0.1
 pyaml==25.5.0
-python-gitlab==6.2.0
+python-gitlab==6.4.0
 rdflib==7.1.3
 requests==2.32.3
 SPARQLTransformer==2.4.0