Update python-dateutil requirement from >= 2.8.2 to >=2.9.0.post0

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@2.8.2...2.9.0.post0)

---
updated-dependencies:
- dependency-name: python-dateutil
  dependency-version: 2.9.0.post0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

pyproject.toml

@@ -13,7 +13,7 @@ include = ["openapi_client/py.typed"]
 python = "^3.8"
 
 urllib3 = ">= 1.25.3 < 3.0.0"
-python-dateutil = ">= 2.8.2"
+python-dateutil = ">=2.9.0.post0"
 pydantic = ">= 2"
 typing-extensions = ">= 4.7.1"