message: update robot push information in README
diff: @@ -95,8 +95,8 @@ $ make install
  # verify
  $ python -c 'import opentrons; print(opentrons.__version__)' # > prints version
  -# run with a real robot
  -$ OT_ROBOT_CONFIG=[your_robot_serial_number] make dev
  +# push API to a USB connected robot
  +$ make push
  # run with a virtual robot
  $ ENABLE_VIRTUAL_SMOOTHIE=true make dev
  