createRelease(options, cb) {
      return this._request('POST', `/repos/${this.__fullname}/releases`, options, cb);
   }
Create a new release
@see https://developer.github.com/v3/repos/releases/#create-a-release
@param {Object} options - the description of the release
@param {Requestable.callback} cb - will receive the newly created release
@return {Promise} - the promise for the http request