Bump black from 21.9b0 to 21.10b0 (#636)

Bumps [black](https://github.com/psf/black) from 21.9b0 to 21.10b0.
- [Release notes](https://github.com/psf/black/releases)
- [Changelog](https://github.com/psf/black/blob/main/CHANGES.md)
- [Commits](https://github.com/psf/black/commits)

---
updated-dependencies:
- dependency-name: black
  dependency-type: direct:production
...

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements/test.txt

@@ -4,6 +4,6 @@ pytest-cov==3.0.0
 pytest-asyncio==0.16.0
 flake8==4.0.1
 mypy==0.910
-black==21.9b0
+black==21.10b0
 isort==5.9.3
 -r ci.txt