Update black to 20.8b1

[pyup-bot]

This PR updates black from 19.3b0 to 20.8b1.

Changelog

### 20.8b1 ``` _Packaging_ - explicitly depend on Click 7.1.2 or newer as `Black` no longer works with versions older than 7.0 ``` ### 20.8b0 ``` _Black_ - re-implemented support for explicit trailing commas: now it works consistently within any bracket pair, including nested structures (1288 and duplicates) - `Black` now reindents docstrings when reindenting code around it (1053) - `Black` now shows colored diffs (1266) - `Black` is now packaged using 'py3' tagged wheels (1388) - `Black` now supports Python 3.8 code, e.g. star expressions in return statements (1121) - `Black` no longer normalizes capital R-string prefixes as those have a community-accepted meaning (1244) - `Black` now uses exit code 2 when specified configuration file doesn't exit (1361) - `Black` now works on AWS Lambda (1141) - added `--force-exclude` argument (1032) - removed deprecated `--py36` option (1236) - fixed `--diff` output when EOF is encountered (526) - fixed ` fmt: off` handling around decorators (560) - fixed unstable formatting with some ` type: ignore` comments (1113) - fixed invalid removal on organizing brackets followed by indexing (1575) - introduced `black-primer`, a CI tool that allows us to run regression tests against existing open source users of Black (1402) - introduced property-based fuzzing to our test suite based on Hypothesis and Hypothersmith (1566) - implemented experimental and disabled by default long string rewrapping (1132), hidden under a `--experimental-string-processing` flag while it's being worked on; this is an undocumented and unsupported feature, you lose Internet points for depending on it (1609) Vim plugin - prefer virtualenv packages over global packages (1383) ``` ### 19.10b0 ``` - added support for PEP 572 assignment expressions (711) - added support for PEP 570 positional-only arguments (943) - added support for async generators (593) - added support for pre-splitting collections by putting an explicit trailing comma inside (826) - added `black -c` as a way to format code passed from the command line (761) - --safe now works with Python 2 code (840) - fixed grammar selection for Python 2-specific code (765) - fixed feature detection for trailing commas in function definitions and call sites (763) - ` fmt: off`/` fmt: on` comment pairs placed multiple times within the same block of code now behave correctly (1005) - _Black_ no longer crashes on Windows machines with more than 61 cores (838) - _Black_ no longer crashes on standalone comments prepended with a backslash (767) - _Black_ no longer crashes on `from` ... `import` blocks with comments (829) - _Black_ no longer crashes on Python 3.7 on some platform configurations (494) - _Black_ no longer fails on comments in from-imports (671) - _Black_ no longer fails when the file starts with a backslash (922) - _Black_ no longer merges regular comments with type comments (1027) - _Black_ no longer splits long lines that contain type comments (997) - removed unnecessary parentheses around `yield` expressions (834) - added parentheses around long tuples in unpacking assignments (832) - added parentheses around complex powers when they are prefixed by a unary operator (646) - fixed bug that led _Black_ format some code with a line length target of 1 (762) - _Black_ no longer introduces quotes in f-string subexpressions on string boundaries (863) - if _Black_ puts parenthesis around a single expression, it moves comments to the wrapped expression instead of after the brackets (872) - `blackd` now returns the version of _Black_ in the response headers (1013) - `blackd` can now output the diff of formats on source code when the `X-Diff` header is provided (969) ```

Links

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

[dmuhs]

Dropped due to missing pypy support