code: public void shareProjectWithGroup(GitlabAccessLevel accessLevel, String expiration, GitlabGroup group, GitlabProject project) throws IOException {
          Query query = new Query()
                  .append("group_id", group.getId().toString())
                  .append("group_access", String.valueOf(accessLevel.accessValue))
                  .appendIf("expires_at", expiration);
  
          String tailUrl = GitlabProject.URL + "/" + project.getId() + "/share" + query.toString();
          dispatch().to(tailUrl, Void.class);
      }
docs: Share a project with a group.
  
  @param accessLevel The permissions level to grant the group.
  @param group       The group to share with.
  @param project     The project to be shared.
  @param expiration  Share expiration date in ISO 8601 format: 2016-09-26 or {@code null}.
  @throws IOException on gitlab api call error