build(deps): update python-dateutil requirement from ~=2.8 to ~=2.9

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@2.8.0...2.9.0.post0)

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

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

requirements.txt

@@ -1,5 +1,5 @@
 jsonpickle~=3.3.0
-python-dateutil~=2.8
+python-dateutil~=2.9
 apimatic-core-interfaces~=0.1.0
 requests~=2.31
 setuptools>=68.0.0