chore(deps-dev): bump types-python-dateutil

Bumps [types-python-dateutil](https://github.com/typeshed-internal/stub_uploader) from 2.9.0.20250708 to 2.9.0.20250809.
- [Commits](https://github.com/typeshed-internal/stub_uploader/commits)

---
updated-dependencies:
- dependency-name: types-python-dateutil
  dependency-version: 2.9.0.20250809
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

requirements-dev.txt

@@ -110,7 +110,7 @@ tomlkit==0.13.3 ; python_version >= '3.7'
 
 trio==0.30.0
 
-types-python-dateutil==2.9.0.20250708
+types-python-dateutil==2.9.0.20250809
 
 types-requests==2.32.4.20250611; python_version >= '3.7'
 urllib3==2.5.0 ; python_version >= '3.7'