Merge Request Dependency Improvements
## Problem to Solve
[Merge request dependencies](https://docs.gitlab.com/ee/user/project/merge_requests/merge_request_dependencies.html) currently only provide minimal support for defining single level dependencies and a lack of complex merge orders. Dependencies also don't provide automatic updates in dependent changes to target the appropriate branch.
## Additional Details
Dependency limitations are documented in https://docs.gitlab.com/ee/user/project/merge_requests/merge_request_dependencies.html#limitations
## Proposal
Improvements should merge request dependencies should be addressed through the linked issues.
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