message: Update tensorboard dependency to 2.0.x
  Also updates tb-nightly dependency to 2.1.x.
  TensorBoard release:
  Nightly release:
diff: @@ -62,7 +62,7 @@ REQUIRED_PACKAGES = [
  'opt_einsum >= 2.3.2',
  'six >= 1.10.0',
  'protobuf >= 3.6.1',
  - 'tensorboard >= 1.15.0, < 1.16.0',
  + 'tensorboard >= 2.0.0, < 2.1.0',
  'tensorflow_estimator >= 1.14.0rc0, < 1.15.0rc0',
  'termcolor >= 1.1.0',
  'wrapt >= 1.11.1',
  @@ -95,7 +95,7 @@ else:
  if 'tf_nightly' in project_name:
  for i, pkg in enumerate(REQUIRED_PACKAGES):
  if 'tensorboard' in pkg:
  - REQUIRED_PACKAGES[i] = 'tb-nightly >= 2.0.0a0, < 2.1.0a0'
  + REQUIRED_PACKAGES[i] = 'tb-nightly >= 2.1.0a0, < 2.2.0a0'
  elif 'tensorflow_estimator' in pkg and '2.0' in project_name:
  REQUIRED_PACKAGES[i] = 'tensorflow-estimator-2.0-preview'
  elif 'tensorflow_estimator' in pkg:
  