code: public GitlabProjectMember updateProjectMember(Integer projectId, Integer userId, GitlabAccessLevel accessLevel) throws IOException {
          return updateProjectMember(projectId, userId, accessLevel, null);
      }
docs: Updates a project member.
  
  @param projectId   the project id
  @param userId      the user id
  @param accessLevel the updated access level for the specified user
  @return GitLabProjectMember with updated access level on success
  @throws IOException on Gitlab API call error