Update black to 21.10b0

[pyup-bot]

This PR updates black from 21.9b0 to 21.10b0.

Changelog

21.10b0

_Black_

- Document stability policy, that will apply for non-beta releases (2529)
- Add new `--workers` parameter (2514)
- Fixed feature detection for positional-only arguments in lambdas (2532)
- Bumped typed-ast version minimum to 1.4.3 for 3.10 compatiblity (2519)
- Fixed a Python 3.10 compatibility issue where the loop argument was still being passed
even though it has been removed (2580)
- Deprecate Python 2 formatting support (2523)

_Blackd_

- Remove dependency on aiohttp-cors (2500)
- Bump required aiohttp version to 3.7.4 (2509)

_Black-Primer_

- Add primer support for --projects (2555)
- Print primer summary after individual failures (2570)

Integrations

- Allow to pass `target_version` in the vim plugin (1319)
- Install build tools in docker file and use multi-stage build to keep the image size
down (2582)

Links

• PyPI: https://pypi.org/project/black
• Changelog: https://pyup.io/changelogs/black/
• Repo: https://github.com/psf/black

[pyup-bot]

Closing this in favor of #271