add pre-commit py3.6 test and extra info flags
This MR will add a new precommit test that uses py3.6, and adds two additional flags to the pre-commit tests:
-
--show-diff-on-failure
: when hooks fail, run git diff directly afterward to show what changes due to the pre-commit. -
--verbose
: produce hook output independent of success (eg. the time it takes to run and some other additional info)