Include git activity in group statistics
Problem to solve
We're trying to track for inactive groups (which can point to per-group resources that can be potentially be shut down or hibernated for cost savings) and currently have to iterate through the group projects and check the last_activity_at of every project. However we're seeing this date isn't always accurate. In addition to the 15 minute delay due to caching (for UI performance), we're seeing some projects not updated more than a hour after the last push.
Proposal
Add last_activity_at and last_activity_project field to groups, accessible via API, and whenever a project has its last_activity_at updated, also update the group with matching date and ID of the project.
What does success look like, and how can we measure that?
The response to an HTTP GET to <server>/api/v4/groups/<id> includes the last project with Git activity and the date+time of that activity.