[BE] Support `fallback_behavior` for approval policies
We want to introduce the fallback_behavior
to merge request approval policies as outlined in &10816 (closed):
The idea for MVC is quite simple:
- we add toggle to YAML mode only,
- with the toggle enabled (potentially something like
fallback_behavior: { fail: closed }
) we will behave as we are right now,- with the toggle disabled (potentially something like
fallback_behavior: { fail: open }
) we will not require approvals when policy or project is misconfigured,- we use
fallback_behavior: { fail: open }
format to allow for further extensions in the future, potentially we could have a list of scenarios where we want to have different scenarios or some exceptions, like we had for many previous features- the fail open option can be defined per policy.
Edited by Dominic Bauer