Bump mypy from 0.812 to 0.910

Bumps [mypy](https://github.com/python/mypy) from 0.812 to 0.910.
- [Release notes](https://github.com/python/mypy/releases)
- [Commits](python/mypy@v0.812...v0.910)

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

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

requirements-test.txt

@@ -1,9 +1,9 @@
-black==21.5b1
+black==21.9b0
 flake8==3.8.*
 isort==5.9.*
 mock==4.0.3
 mongomock==3.23.*
-mypy==0.812
+mypy==0.910
 pytest==6.2.*
 pytest-cov==2.12.*
 pytest-vcr==1.0.*