Automation for closed ingestion requests

When closing an ingestion PR, sometimes the people who submitted the corresponding issue are unaware of it (e.g., #5439). I would like an automation that:

* Triggers when an ingestion PR closes
* Finds the linked issue
* Adds the following comment:

> This issue has been closed automatically because an ingestion request has been completed. Within a half hour or so, you should be able to find your event or volumes live on the Anthology.

It ideally would include a link to the new volume or event.