pre-commit: prep and return repo
pre-commit: prep and return repo

We want to invoke pre-commit on the code that's actually being
submitted, so we actually test what will be part of the commit.

This does that, unless PRE_COMMIT_DIRTY=true is in environ.

[ci skip]

sgrayban/sks_spider,philpennock/sks_spider,sgrayban/sks_spider,sgrayban/sks_spider,philpennock/sks_spider,philpennock/sks_spider