docs: public Milestone createGroupMilestone(Object groupIdOrPath, String title, String description, Date dueDate, Date startDate) throws GitLabApiException {
          GitLabApiForm formData = new GitLabApiForm()
                  .withParam("title", title, true)
                  .withParam("description", description)
                  .withParam("due_date", dueDate)
                  .withParam("start_date", startDate);
          Response response = post(Response.Status.CREATED, formData,
                  "groups", getGroupIdOrPath(groupIdOrPath), "milestones");
          return (response.readEntity(Milestone.class));
      }