chore: bump types-python-dateutil from 2.9.0.20260323 to 2.9.0.20260402 (#462)

Bumps [types-python-dateutil](https://github.com/python/typeshed) from 2.9.0.20260323 to 2.9.0.20260402.
- [Commits](https://github.com/python/typeshed/commits)

---
updated-dependencies:
- dependency-name: types-python-dateutil
  dependency-version: 2.9.0.20260402
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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