repository/commits path parameter returns all commits in the project if only one commit is present
<!--IssueSummary start-->
<details>
<summary>
Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards.
</summary>
- [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=559254)
</details>
<!--IssueSummary end-->
<!---
Please read this!
Before opening a new issue, make sure to search for keywords in the issues
filtered by the "regression" or "type::bug" label:
- https://gitlab.com/gitlab-org/gitlab/issues?label_name%5B%5D=regression
- https://gitlab.com/gitlab-org/gitlab/issues?label_name%5B%5D=type::bug
and verify the issue you're about to submit isn't a duplicate.
--->
## Summary
The `GET /projects/:id/repository/commits` API will `follow` when only a single file is requested. This is because the `FindCommits` RPC in Gitaly always sets the `follow` field to `true` when there is only a single file.
When multiple files are passed, the `follow` parameter is not always set to `true`.
## Proposal
A new flag could be introduced to the `/commits` API that would allow you to specify the `follow` behavior.
issue