chore(deps): bump python-dateutil in /docs/main

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>

docs/main/requirements.txt

@@ -19,7 +19,7 @@ pathspec==0.11.2
 platformdirs==3.10.0
 Pygments==2.16.1
 pymdown-extensions==10.3
-python-dateutil==2.8.2
+python-dateutil==2.9.0.post0
 PyYAML==6.0.1
 pyyaml_env_tag==0.1
 regex==2023.8.8