chore(deps-dev): Bump the development-dependencies group with 4 updates

Bumps the development-dependencies group with 4 updates: [mypy](https://github.com/python/mypy), [types-python-dateutil](https://github.com/python/typeshed), [types-requests](https://github.com/python/typeshed) and [types-simplejson](https://github.com/python/typeshed).


Updates `mypy` from 1.20.0 to 1.20.1
- [Changelog](https://github.com/python/mypy/blob/master/CHANGELOG.md)
- [Commits](python/mypy@v1.20.0...v1.20.1)

Updates `types-python-dateutil` from 2.9.0.20260402 to 2.9.0.20260408
- [Commits](https://github.com/python/typeshed/commits)

Updates `types-requests` from 2.33.0.20260402 to 2.33.0.20260408
- [Commits](https://github.com/python/typeshed/commits)

Updates `types-simplejson` from 3.20.0.20260402 to 3.20.0.20260408
- [Commits](https://github.com/python/typeshed/commits)

---
updated-dependencies:
- dependency-name: mypy
  dependency-version: 1.20.1
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: development-dependencies
- dependency-name: types-python-dateutil
  dependency-version: 2.9.0.20260408
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: development-dependencies
- dependency-name: types-requests
  dependency-version: 2.33.0.20260408
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: development-dependencies
- dependency-name: types-simplejson
  dependency-version: 3.20.0.20260408
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: development-dependencies
...

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Author: dependabot[bot]