Before-commit

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

Fixes
- Fix race condition when stashing files in multiple parallel invocations
- 1881 PR by adamchainz.
- 1880 issue by adamchainz.

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

Features
- Upgrade rbenv.
- 1854 PR by asottile.
- 1848 issue by sirosen.

Fixes
- Give command length a little more room when running batch files on windows
so underlying commands can expand further.
- 1864 PR by asottile.
- pre-commit/mirrors-prettier7 issue by DeltaXWizard.
- Fix permissions of root folder in ruby archives.
- 1868 PR by asottile.

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

Fixes
- Fix r hooks when hook repo is a package
- 1831 PR by lorenzwalthert.

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

Features
- Improve warning for mutable ref.
- 1809 PR by JamMarHer.
- Add support for `post-merge` hook.
- 1800 PR by psacawa.
- 1762 issue by psacawa.
- Add `r` as a supported hook language.
- 1799 PR by lorenzwalthert.

Fixes
- Fix `pre-commit install` on `subst` / network drives on windows.
- 1814 PR by asottile.
- 1802 issue by goroderickgo.
- Fix installation of `local` golang repositories for go 1.16.
- 1818 PR by rafikdraoui.
- 1815 issue by rafikdraoui.

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

Fixes
- Fix `language: golang` repositories containing recursive submodules
- 1788 issue by gaurav517.
- 1789 PR by paulhfischer.

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

Features
- Allow `ci` as a top-level map for configuration for https://pre-commit.ci
- 1735 PR by asottile.
- Add warning for mutable `rev` in configuration
- 1715 PR by paulhfischer.
- 974 issue by asottile.
- Add warning for `/*` in top-level `files` / `exclude` regexes
- 1750 PR by paulhfischer.
- 1702 issue by asottile.
- Expose `PRE_COMMIT_REMOTE_BRANCH` environment variable during `pre-push`
hooks
- 1770 PR by surafelabebe.
- Produce error message for `language` / `language_version` for non-installable
languages
- 1771 PR by asottile.

Fixes
- Fix execution in worktrees in subdirectories of bare repositories
- 1778 PR by asottile.
- 1777 issue by s0undt3ch.