code: public List<Milestone> getMilestones(Object projectIdOrPath, int page, int perPage) throws GitLabApiException {
          Response response = get(Response.Status.OK, getPageQueryParams(page, perPage),
                  "projects", getProjectIdOrPath(projectIdOrPath), "milestones");
          return (response.readEntity(new GenericType<List<Milestone>>() {}));
      }
docs: Get a list of project milestones.
  
  @param projectIdOrPath the project in the form of an Integer(ID), String(path), or Project instance
  @param page the page number to get
  @param perPage how many milestones per page
  @return the milestones associated with the specified project
  @throws GitLabApiException if any exception occurs