message: Update README.md
  bytestring over the use of decode()
diff: @@ -69,8 +69,8 @@ $ python
  >>> tf.add(1, 2).numpy()
  3
  >>> hello = tf.constant('Hello, TensorFlow!')
  ->>> hello.numpy().decode('utf-8')
  -'Hello, TensorFlow!'
  +>>> hello.numpy()
  +b'Hello, TensorFlow!'
  ```
  For more examples, see the
  