Update dangerfile to exclude docs ci yaml
What does this MR do?
This is a resubmission of https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/30220 under a different branch name to make sure the full pipeline is run. See original MR for discussion.
Related to https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/30220
Related to https://gitlab.com/gitlab-com/gitlab-docs/issues/397
Edited by Marcel Amirault