GET /projects/:id/repository/commits supports a new optional attribute
to list the commits in order.

At the moment the possible values are `none` (default) and `topo`
witch implements (--topo-order).
https://git-scm.com/docs/git-log#Documentation/git-log.txt---topo-order

This was introduced in Gitaly v1.86.0
https://gitlab.com/gitlab-org/gitaly/-/blob/master/CHANGELOG.md#v1860
https://gitlab.com/gitlab-org/gitaly/-/merge_requests/1791