Bump mypy from 1.4.1 to 1.6.1

Bumps [mypy](https://github.com/python/mypy) from 1.4.1 to 1.6.1.
- [Changelog](https://github.com/python/mypy/blob/master/CHANGELOG.md)
- [Commits](python/mypy@v1.4.1...v1.6.1)

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

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

requirements/lint.txt

@@ -1,2 +1,2 @@
-mypy==1.4.1; implementation_name=="cpython"
+mypy==1.6.1; implementation_name=="cpython"
 pre-commit==3.5.0; python_version>="3.8"