Add a warning when the pipeline was created more than 6 hours ago
Context
See this broken master incident: gitlab-org/quality/engineering-productivity/master-broken-incidents#379 (closed)
Specifically, this explanation: gitlab-org/quality/engineering-productivity/master-broken-incidents#379 (comment 1222574915)
Goal
We would like to add a warning when a MR is merged, and its latest pipeline was started more than 6 hours ago.