Bump mypy from 0.971 to 0.991 (#107)

Bumps [mypy](https://github.com/python/mypy) from 0.971 to 0.991.
- [Release notes](https://github.com/python/mypy/releases)
- [Commits](python/mypy@v0.971...v0.991)

---
updated-dependencies:
- dependency-name: mypy
  dependency-type: direct:production
  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.txt

@@ -4,7 +4,7 @@ autoflake==1.4
 black==23.1.0
 flake8==3.9.2
 isort==5.10.0
-mypy==0.971
+mypy==0.991
 pre-commit==2.17.0
 pytest==7.0.0
 pytest-cov==4.0.0