* move doc link checker to a cron
* change to test
* point at secret
* access environment for more-secrets
* improve formatting
* one more format update
* switch back to only cron / dispatch settings
* improve link checker
* use ref instead of base_ref
* remove base, always compare to master for modified
* add failing to test
* don't do quiet for testing
* switch error to 404 not 403
* yes to both
* turn off verbose mode
* fix
* actually check things
* fix outstanding link problems
* revet change to run for everything
* use new format
* ignore gitbook failures
* switch back to only running on master