[New Audit Event]: Audit event missing when MR approval rules are changed

Audit need

When MR approval rules are updated, there is no way to determine who updated them or when those rules were updated.

Proposal

Whenever MR approval rules are changed, create an Audit event with the user that updated the MR rules, the previous parameter and the the new parameter for any that were updated.

Streaming-only event or normal event?

Streaming-only