message: fix: correct the documentation
  Publish with custom attributes resolves same as publish without custom attributes.
diff: @@ -156,8 +156,7 @@ function publishMessageWithCustomAttributes(topicName, data) {
  .topic(topicName)
  .publisher()
  .publish(dataBuffer, customAttributes)
  - .then(results => {
  - const messageId = results[0];
  + .then(messageId => {
  console.log(`Message ${messageId} published.`);
  })
  .catch(err => {
  