Update python-dateutil requirement from ~=2.6 to ~=2.9 in /requirements

Updates the requirements on [python-dateutil](https://github.com/dateutil/dateutil) to permit the latest version.
- [Release notes](https://github.com/dateutil/dateutil/releases)
- [Changelog](https://github.com/dateutil/dateutil/blob/master/NEWS)
- [Commits](dateutil/dateutil@2.6.0...2.9.0.post0)

---
updated-dependencies:
- dependency-name: python-dateutil
  dependency-type: direct:production
...

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

requirements/requirements.txt

@@ -1,5 +1,5 @@
 PyYAML>=5.4.0,<7.0.0
 combo_lock~=0.2
-python-dateutil~=2.6
+python-dateutil~=2.9
 ovos-utils >= 0.0.37
 rich-click ~=1.6