build(deps-dev): bump mypy from 1.19.1 to 1.20.0 (#750)

Bumps [mypy](https://github.com/python/mypy) from 1.19.1 to 1.20.0.
- [Changelog](https://github.com/python/mypy/blob/master/CHANGELOG.md)
- [Commits](python/mypy@v1.19.1...v1.20.0)

---
updated-dependencies:
- dependency-name: mypy
  dependency-version: 1.20.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements-dev.txt

@@ -5,4 +5,4 @@ flake8-bandit==4.1.1
 flake8-bugbear==25.11.29
 flake8-import-order==0.19.2
 flake8-requirements==2.3.0
-mypy==1.19.1; implementation_name=="cpython"
+mypy==1.20.0; implementation_name=="cpython"