build(deps): bump python-dateutil from 2.8.1 to 2.8.2 in /backend

Bumps [python-dateutil](https://github.com/dateutil/dateutil) from 2.8.1 to 2.8.2.
- [Release notes](https://github.com/dateutil/dateutil/releases)
- [Changelog](https://github.com/dateutil/dateutil/blob/master/NEWS)
- [Commits](dateutil/dateutil@2.8.1...2.8.2)

---
updated-dependencies:
- dependency-name: python-dateutil
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

backend/requirements.txt

@@ -7,7 +7,7 @@ Flask-Cors==3.0.10
 flask-talisman==0.7.0
 google-cloud-storage==1.38.0
 gunicorn==20.1.0
-python-dateutil==2.8.1
+python-dateutil==2.8.2
 pytoml==0.1.21
 redis==3.5.3
 swagger-ui-bundle==0.0.8