Bump python-dateutil from 2.8.2 to 2.9.0.post0

Bumps [python-dateutil](https://github.com/dateutil/dateutil) from 2.8.2 to 2.9.0.post0.
- [Release notes](https://github.com/dateutil/dateutil/releases)
- [Changelog](https://github.com/dateutil/dateutil/blob/master/NEWS)
- [Commits](dateutil/dateutil@2.8.2...2.9.0.post0)

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

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

Author: dependabot[bot]

install/testing_requirements.txt

@@ -4,6 +4,6 @@ pytest==8.0.2
 pytest-cov==4.1.0
 pytest-timeout==2.2.0
 mock==5.1.0
-python-dateutil==2.8.2
+python-dateutil==2.9.0.post0
 anyio==4.3.0
 matplotlib==3.8.3