The git repo, sure. It's all the workflow stuff around it that is harder to migrate -- issue reporting, what workflow you use for code review and merging changes, CI, etc. Those too can be moved, but I wouldn't use the word "trivial" -- there's potentially a lot of work there with migrating old issue data across, figuring out what changes to everybody's dev workflow the new platform will require versus what can stay the same, adjusting or rewriting CI configs, and so on.