Bump mypy from 1.8.0 to 1.9.0 (#385)

Bumps [mypy](https://github.com/python/mypy) from 1.8.0 to 1.9.0.
- [Changelog](https://github.com/python/mypy/blob/master/CHANGELOG.md)
- [Commits](python/mypy@v1.8.0...1.9.0)

---
updated-dependencies:
- dependency-name: mypy
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements/testing.txt

@@ -10,5 +10,5 @@ pytest-cov==4.0.0
 pytest-timeout==2.3.1
 setuptools==69.1.1
 twine==5.0.0
-mypy==1.8.0
+mypy==1.9.0
 types-pyyaml==6.0.12.12