Pre-commit

==================

Fixes
- Prevent infinite recursion of post-checkout on clone
- 1497 PR by asottile.
- 1496 issue by admorgan.

==================

Features
- Expose a `PRE_COMMIT=1` environment variable when running hooks
- 1467 PR by tech-chad.
- 1426 issue by lorenzwalthert.

Fixes
- Fix `UnicodeDecodeError` on windows when using the `py` launcher to detect
executables with non-ascii characters in the path
- 1474 PR by asottile.
- 1472 issue by DrFobos.
- Fix `DeprecationWarning` on python3.9 for `random.shuffle` method
- 1480 PR by asottile.
- 1479 issue by isidentical.
- Normalize slashes earlier such that global `files` / `exclude` use forward
slashes on windows as well.
- 1494 PR by asottile.
- 1476 issue by harrybiddle.

==================

Features
- Add support for `post-commit` hooks
- 1415 PR by ModischFabrications.
- 1411 issue by ModischFabrications.
- Silence pip version warning in python installation error
- 1412 PR by asottile.
- Improve python `healthy()` when upgrading operating systems.
- 1431 PR by asottile.
- 1427 issue by ahonnecke.
- `language: python_venv` is now an alias to `language: python` (and will be
removed in a future version).
- 1431 PR by asottile.
- Speed up python `healthy()` check.
- 1431 PR by asottile.
- `pre-commit autoupdate` now tries to maintain quoting style of `rev`.
- 1435 PR by marcjay.
- 1434 issue by marcjay.

Fixes
- Fix installation of go modules in `repo: local`.
- 1428 PR by scop.
- Fix committing with unstaged files and a failing `post-checkout` hook.
- 1422 PR by domodwyer.
- 1418 issue by domodwyer.
- Fix installation of node hooks with system node installed on freebsd.
- 1443 PR by asottile.
- 1440 issue by jockej.
- Fix ruby hooks when `GEM_PATH` is set globally.
- 1442 PR by tdeo.
- Improve error message when `pre-commit autoupdate` /
`pre-commit migrate-config` are run but the pre-commit configuration is not
valid yaml.
- 1448 PR by asottile.
- 1447 issue by rpdelaney.

==================

Features
- Calculate character width using `east_asian_width`
- 1378 PR by sophgn.
- Use `language_version: system` by default for `node` hooks if `node` / `npm`
are globally installed.
- 1388 PR by asottile.

Fixes
- No longer use a hard-coded user id for docker hooks on windows
- 1371 PR by killuazhu.
- Fix colors on windows during `git commit`
- 1381 issue by Cielquan.
- 1382 PR by asottile.
- Produce readable error message for incorrect argument count to `hook-impl`
- 1394 issue by pip9ball.
- 1395 PR by asottile.
- Fix installations which involve an upgrade of `pip` on windows
- 1398 issue by xiaohuazi123.
- 1399 PR by asottile.
- Preserve line endings in `pre-commit autoupdate`
- 1402 PR by utek.

==================

Features
- Add support for the `post-checkout` hook
- 1120 issue by domenkozar.
- 1339 PR by andrewhare.
- Add more readable `--from-ref` / `--to-ref` aliases for `--source` /
`--origin`
- 1343 PR by asottile.

Fixes
- Make sure that `--commit-msg-filename` is passed for `commit-msg` /
`prepare-commit-msg`.
- 1336 PR by particledecay.
- 1341 PR by particledecay.
- Fix crash when installation error is un-decodable bytes
- 1358 issue by Guts.
- 1359 PR by asottile.
- Fix python `healthy()` check when `python` executable goes missing.
- 1363 PR by asottile.
- Fix crash when script executables are missing shebangs.
- 1350 issue by chriselion.
- 1364 PR by asottile.

Misc.
- pre-commit now requires python>=3.6.1 (previously 3.6.0)
- 1346 PR by asottile.

==================

Fixes
- Temporarily restore python 3.6.0 support (broken in 2.0.0)
- reported by obestwalter.
- 081f3028 by asottile.