message: change license year from 2017 to 2020
diff: #!/bin/bash
  -# Copyright 2017 The TensorFlow Authors. All Rights Reserved.
  +# Copyright 2020 The TensorFlow Authors. All Rights Reserved.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  