message: Install future with quotes to handle the > symbol
  pip install future>=0.17.1 will run the command `pip install future`
  and redirect the output to a file called `=0.17.1`. By putting the command
  in quotes the redirection is avoided and proper command is run.
diff: @@ -48,8 +48,8 @@ pip3 install virtualenv
  # Install six and future.
  pip2 install --upgrade six==1.12.0
  pip3 install --upgrade six==1.12.0
  -pip2 install future>=0.17.1
  -pip3 install future>=0.17.1
  +pip2 install "future>=0.17.1"
  +pip3 install "future>=0.17.1"
  # Install absl-py.
  pip2 install --upgrade absl-py
  