High number of GitHub emails after every Dinghyfile update

Issue

After enabling the Dinghy GitHub notifier, users may find that there is additional comments in a Pull Request.  This is so that Dinghy can provide more robust feedback information to the persons initiating the Pull Request to allow them to make decisions on the PR.   A consequence is that users may experience a high number of emails generated after every update to a module that occurs.  This is because module updates may have chain reactions to the multiple Dinghyfiles that may be using them.

Cause

After an update to a commonly used module, all of the associated pipelines are re-rendered, triggering a potentially high amount of API calls to Github. This in turn generates a lot of emails from Github and may potentially manifest itself by triggering rate-limits.