[Feature request] Avoid missing Terraform applies by adding Atlantis user as MR approver

[blastik]

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• I'd be willing to implement this feature (contributing guide)

Describe the user story

We are using Atlantis in Gitlab. We have several workspaces, typically linked to an AWS account (environment) and a region and each of them with its own workflow. Some of the workflows have dependencies on another workflow (that way we enforce things like dev being applied first and then production). We also enabled automerge.
Now, currently there is a chance for engineers missing out pending terraform applies (lets say, they apply dev and sandbox but not production). They could merge any time and that would make that workspace out of sync with what has been committed to the main branch. Obviously we've set approved apply requirement for some workspaces but that doesnt solve the issue.

Describe the solution you'd like

What if Atlantis, as part of the automerge process, also adds himself as approver once users finish doing all terraform applies. That way we could add a Gitlab rules so MRs cannot be merged without Atlantis user approval.
So the process would be: User finishes the last terraform apply > then Atlantis add himself as approver > now both Atlantis and the user could merge the MR (because of the Gitlab MR and CODEOWNERS rules)

Describe the drawbacks of your solution

N/A

Describe alternatives you've considered

Is there any? 🤔