docs: public List<Milestone> getGroupMilestones(Object groupIdOrPath, int page, int perPage) throws GitLabApiException {
          Response response = get(Response.Status.OK, getPageQueryParams(page, perPage),
                  "groups", getGroupIdOrPath(groupIdOrPath), "milestones");
          return (response.readEntity(new GenericType<List<Milestone>>() {}));
      }