Pre-commit

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

Features
- Setting `SKIP=...` skips installation as well.
- 1875 PR by asottile.
- pre-commit-ci/issues53 issue by TylerYep.
- Attempt to mount from host with docker-in-docker.
- 1888 PR by okainov.
- 1387 issue by okainov.
- Enable `repo: local` for `r` hooks.
- 1878 PR by lorenzwalthert.
- Upgrade `ruby-build` and `rbenv`.
- 1913 PR by jalessio.

Fixes
- Better detect `r` packages.
- 1898 PR by lorenzwalthert.
- Avoid warnings with mismatched `renv` versions.
- 1841 PR by lorenzwalthert.
- Reproducibly produce ruby tar resources.
- 1915 PR by asottile.

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

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.