Bump mypy from 1.7.1 to 1.8.0 (#118)

Bumps [mypy](https://github.com/python/mypy) from 1.7.1 to 1.8.0.
- [Changelog](https://github.com/python/mypy/blob/master/CHANGELOG.md)
- [Commits](python/mypy@v1.7.1...v1.8.0)

---
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.txt

@@ -1,6 +1,6 @@
 blue==0.9.1
 isort==5.13.2
-mypy==1.7.1
+mypy==1.8.0
 pip-chill==1.0.3
 pygithub==2.1.1
 pytest-cov==4.1.0