Verified commits push rule check
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### Problem to solve
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There is a lack of an option to set up checking if a commit is verified in push rules. Checking if a commit signed or not works, but the unverified commits that are signed are still able to pass.
### Intended users
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Enterprise user here, we really need both of those features.
### Further details
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It's basic security utility which had to be missed.
### Proposal
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Add button in push rules to require verified commits.
### Permissions and Security
<!-- What permissions are required to perform the described actions? Are they consistent with the existing permissions as documented for users, groups, and projects as appropriate? Is the proposed behaviour consistent between the UI, API, and other access methods (e.g. email replies)?-->
### Documentation
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Add all known Documentation Requirements here, per https://docs.gitlab.com/ee/development/documentation/feature-change-workflow.html#documentation-requirements
If this feature requires changing permissions, this document https://docs.gitlab.com/ee/user/permissions.html must be updated accordingly. -->
### Testing
<!-- What risks does this change pose? How might it affect the quality of the product? What additional test coverage or changes to tests will be needed? Will it require cross-browser testing? See the test engineering process for further help: https://about.gitlab.com/handbook/engineering/quality/test-engineering/ -->
### What does success look like, and how can we measure that?
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### What is the type of buyer?
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### Links / references
issue