Digger currently does not support apply_requirements (like in Atlantis). Coming soon - (#1252)

Workaround

You can use mergeability requirements together with Status Checks to achieve the same. Digger will not apply if the pull request is not in a “mergable” state as specified by GitHub api. This means that if you have a separate status check and you have this check as “required” by branch protection rules then an attempt of digger apply will not go ahead.