Bump mypy from 0.812 to 0.901

Bumps [mypy](https://github.com/python/mypy) from 0.812 to 0.901.
- [Release notes](https://github.com/python/mypy/releases)
- [Commits](python/mypy@v0.812...v0.901)

---
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

@@ -2,7 +2,7 @@
 asynctest~=0.13
 flake8~=3.9
 flake8-docstrings~=1.6
-mypy==0.812
+mypy==0.901
 pylint~=2.8
 pylint-strict-informational==0.1
 pytest~=6.2