Add commit-msg hook

This is the commit-msg hook from:
https://gerrit-review.googlesource.com/tools/hooks/commit-msg

I'm including it here since there should just be a single place that
manages all of our git hooks.

Bug: b/187094215
Change-Id: I60ef07b843fcdbaa944182d5c1611bb4b073a788
1 file changed
tree: 6dec520e4ae94a546221b77b7f14cb75ed84df8b
  1. commit-msg
  2. pre-commit