Track changes in merge request approval settings in the audit log

"Rules" aspect moved to #209222 (closed)

Problem to solve

Tracking changes in merge request approval settings and rules in the audit log

Further details

Client proposed change in Zendesk ticket: https://gitlab.zendesk.com/agent/tickets/103355 (Internal use only)

They asked if the audit logs could address changes to required approvers (how many, enabled/disabled).

Important Note

As of %12.7 Administrators will be able to set instance-wide rules for MR approvals that will restrict these settings at the project level for any non-admins.

Currently scheduled for %12.8 is an iteration to bring this functionality to the group level for .com customers and will follow similar logic: only Group Owners can modify the settings at the project level.

This activity - the modification of MR approval settings - should still be logged, though this detail may affect how it's logged and with what supplemental data.

Proposal

We should log, at the group level the three most important details of the MR approval settings and iterate to include additional settings later. Those three settings, as defined in #39060 (closed) are:

• Prevent approval of merge requests by merge request author
  • e.g. User modified Project to allow merge request authors to approve their own merge requests
  • e.g. User modified Project to deny merge request authors from approving their own merge requests
• Prevent approval of merge requests by merge request committers
  • e.g. User modified Project to allow merge request committers to approve their own merge request
  • e.g. User modified Project to deny merge request authors from approving their own merge requests
• Approvers List changes
  • e.g. User modified approvers for Project to 1 from 2
  • e.g. User modified approvers for Project to 4 from 2

These events should contain a default sort order of Newest to Oldest.