message: Adding release notes for 1.12
diff: # Release 1.12.0
  ## Major Features and Improvements
  -
  +* tf.data optimizations. Users can now represent, get and set options of a tf.data pipeline.
  + tf.data.AUTOTUNE enables the level of parallelism to be determined at runtime.
  +* Keras models can now be directly exported to the SavedModel format and used with Tensorflow Serving.
  ## Breaking Changes
  