message: Make tensorflow cpu an install requirement
  Removed the cpu extra
diff: @@ -68,10 +68,9 @@ install_requires = [
  "numproto==0.2.0", # Apache License 2.0
  "grpcio-tools==1.23.0", # Apache License 2.0
  "mypy-protobuf==1.15", # Apache License 2.0
  + "tensorflow==1.14.0", # Apache 2.0
  ]
  -cpu_require = ["tensorflow==1.14.0"] # Apache 2.0
  -
  gpu_require = ["tensorflow-gpu==1.14.0"] # Apache 2.0
  dev_require = [
  @@ -121,7 +120,6 @@ setup(
  tests_require=tests_require,
  extras_require={
  "test": tests_require,
  - "cpu": cpu_require,
  "gpu": gpu_require,
  "dev": dev_require + tests_require,
  },
  