Bump black from 21.9b0 to 21.10b0 (#632)

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
...

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

Author: dependabot[bot]

requirements/lint.txt

@@ -1,4 +1,4 @@
 mypy==0.910; implementation_name=="cpython"
 flake8==4.0.1
 flake8-pyi==20.10.0; python_version >= "3.6"
-black==21.9b0; python_version >= "3.6" and implementation_name=="cpython"
+black==21.10b0; python_version >= "3.6" and implementation_name=="cpython"