Update black to 21.9b0

[pyup-bot]

This PR updates black from 21.6b0 to 21.9b0.

Changelog

21.9b0

Packaging

- Fix missing modules in self-contained binaries (2466)
- Fix missing toml extra used during installation (2475)

21.8b0

_Black_

- Add support for formatting Jupyter Notebook files (2357)
- Move from `appdirs` dependency to `platformdirs` (2375)
- Present a more user-friendly error if .gitignore is invalid (2414)
- The failsafe for accidentally added backslashes in f-string expressions has been
hardened to handle more edge cases during quote normalization (2437)
- Avoid changing a function return type annotation's type to a tuple by adding a
trailing comma (2384)
- Parsing support has been added for unparenthesized walruses in set literals, set
comprehensions, and indices (2447).
- Pin `setuptools-scm` build-time dependency version (2457)
- Exclude typing-extensions version 3.10.0.1 due to it being broken on Python 3.10
(2460)

_Blackd_

- Replace sys.exit(-1) with raise ImportError as it plays more nicely with tools that
scan installed packages (2440)

Integrations

- The provided pre-commit hooks no longer specify `language_version` to avoid overriding
`default_language_version` (2430)

21.7b0

_Black_

- Configuration files using TOML features higher than spec v0.5.0 are now supported
(2301)
- Add primer support and test for code piped into black via STDIN (2315)
- Fix internal error when `FORCE_OPTIONAL_PARENTHESES` feature is enabled (2332)
- Accept empty stdin (2346)
- Provide a more useful error when parsing fails during AST safety checks (2304)

Docker

- Add new `latest_release` tag automation to follow latest black release on docker
images (2374)

Integrations

- The vim plugin now searches upwards from the directory containing the current buffer
instead of the current working directory for pyproject.toml. (1871)
- The vim plugin now reads the correct string normalization option in pyproject.toml
(1869)
- The vim plugin no longer crashes Black when there's boolean values in pyproject.toml
(1869)

Links

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