Bump mypy from 0.910 to 0.931 (#5538)

* Bump mypy from 0.910 to 0.931

Bumps [mypy](https://github.com/python/mypy) from 0.910 to 0.931.
- [Release notes](https://github.com/python/mypy/releases)
- [Commits](python/mypy@v0.910...v0.931)

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

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

* More useless type annotations

mypy has gone loco

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Dirk Groeneveld <dirkg@allenai.org>

dev-requirements.txt

@@ -4,7 +4,7 @@
 flake8
 
 # Static type checking
-mypy==0.910
+mypy==0.931
 
 # Automatic code formatting
 black==21.12b0