Pre-commit

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

Fixes
- Replace `yaml.load` with safe alternative
- `yaml.load` can lead to arbitrary code execution, though not where it
was used
- issue by tonybaloney.
- 779 PR by asottile.
- Improve not found error with script paths (`./exe`)
- 782 issue by ssbarnea.
- 785 PR by asottile.
- Fix minor buffering issue during `--show-diff-on-failure`
- 796 PR by asottile.
- Default `language_version: python3` for `python_venv` when running in python2
- 794 issue by ssbarnea.
- 797 PR by asottile.
- `pre-commit run X` only run `X` and not hooks with `stages: [...]`
- 772 issue by asottile.
- 803 PR by mblayman.

Misc.
- Improve travis-ci build times by caching rust / swift artifacts
- 781 PR by expobrain.
- Test against python3.7
- 789 PR by expobrain.

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

Fixes
- Fix `pre-push` during a force push without a fetch
- 777 issue by domenkozar.
- 778 PR by asottile.

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

Fixes
- pre-commit now invokes hooks with a consistent ordering of filenames
- issue by mxr.
- 767 PR by asottile.

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

Fixes
- `python_venv` language would leak dependencies when pre-commit was installed
in a `-mvirtualenv` virtualenv
- 755 756 issue and PR by asottile.

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

Features
- Add support for hooks written in `rust`
- 751 PR by chriskuehl.

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

Features
- Add new `python_venv` language which uses the `venv` module instead of
`virtualenv`
- 631 issue by dongyuzheng.
- 739 PR by ojii.
- Include `LICENSE` in distribution
- 745 issue by nicoddemus.
- 746 PR by nicoddemus.

Fixes
- Normalize relative paths for `pre-commit try-repo`
- 750 PR by asottile.