isManagedRepo(owner, repo, cb) {
      log(`Getting repo management by Team ${this.__teamId} for repo ${owner}/${repo}`);
      return this._request204or404(`/teams/${this.__teamId}/repos/${owner}/${repo}`, undefined, cb);
   }
Get repo management status for team
@see https://developer.github.com/v3/orgs/teams/#remove-team-membership
@param {string} owner - Organization name
@param {string} repo - Repo name
@param {Requestable.callback} [cb] - will receive the membership status of added user
@return {Promise} - the promise for the http request