message: Update flex ops documentation
diff: @@ -250,7 +250,18 @@ as is typically required with other delegate types.
  ### Python pip package
  -Python support is actively under development.
  +Flex ops are included in the nightly build of the TensorFlow Python package. You
  +can use TFLite models containing Flex ops by the same Python API as normal
  +TFLite models. The nightly TensorFlow build can be installed with this command:
  +
  +```sh
  +pip install tf-nightly
  +```
  +
  +Flex ops will be added to the TensorFlow Python package's and the
  +`tflite_runtime`
  +[package](https://www.tensorflow.org/lite/guide/python#install_just_the_tensorflow_lite_interpreter)
  +from version 2.3 for Linux and 2.4 for other environments.
  ## Metrics
  