Add ability to approve a MR
### Problem to solve
Add ability to approve a MR.
### Proposal
For me, the most intuitive way for doing this is to add the option when right-clicking on the MR name, same as the option "Checkout MR branch"
### Further details
In some teams, a MR needs the approval of some members. This would ease this process.
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### Links / references
I saw there was a proposal in https://gitlab.com/gitlab-org/gitlab-vscode-extension/-/issues/227, but was closed as duplicate of https://gitlab.com/gitlab-org/gitlab-vscode-extension/-/issues/63. Unfortunately https://gitlab.com/gitlab-org/gitlab-vscode-extension/-/issues/63 did not add this feature.
issue