code: public List<GitlabProject> getGroupProjects(Integer groupId) {
          String tailUrl = GitlabGroup.URL + "/" + groupId + GitlabProject.URL + PARAM_MAX_ITEMS_PER_PAGE;
          return retrieve().getAll(tailUrl, GitlabProject[].class);
      }
docs: Get all the projects for a group.
  
  @param groupId the target group's id.
  @return a list of projects for the group