check_gh should accept local config files rather than trying to read from the remote repo

[thatportugueseguy]

When we are developing against private repos of which we are not admins and can't get auth tokens to, the check_gh function becomes pointless unless we change all the repo details on the payloads to point to a repo we control. This is tedious if we need to test on multiple cases that already exist. It would make more sense to just read from a local file, i'd say.