repo-updater: move vcs/git/MergeBase to gitserver/commands (!36291) · Merge requests · Administrator / sourcegraph · GitLab

Administrator requested to merge ao/move-git-mergeBase-command into main May 31, 2022

Created by: sashaostrikov

Refactoring in scope of https://github.com/sourcegraph/sourcegraph/issues/33280

Closes https://github.com/sourcegraph/sourcegraph/issues/36289

Test plan

Existing tests should pass