Bump mypy from 0.930 to 0.931 (#270)

Bumps [mypy](https://github.com/python/mypy) from 0.930 to 0.931.
- [Release notes](https://github.com/python/mypy/releases)
- [Commits](python/mypy@v0.930...v0.931)

---
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/ci.txt

@@ -1,4 +1,4 @@
-mypy==0.930; implementation_name=="cpython"
+mypy==0.931; implementation_name=="cpython"
 mypy-extensions==0.4.3; implementation_name=="cpython"
 
 -r ci-wheel.txt