message: tflite: Update TF Op select guide
  Applied the following changes:
  Quantization works with Flex delegate
  GPU delegate, NNAPI delegate works with Flex delegate
diff: @@ -261,15 +261,11 @@ TFLite builtin ops and 3 Tensorflow ops. For more details, please see the
  input/output types that are typically available in TensorFlow.
  * Unsupported ops: Control flow ops and ops that require explicit
  initialization from resources, like `HashTableV2`, are not yet supported.
  -* Unsupported optimizations: If you apply an optimization known as
  - [post training quantization](../performance/post_training_quantization.md),
  - only the TensorFlow Lite ops will be quantized (or optimized), but the
  - TensorFlow ops will remain as float (or unoptimized).
  -## Future plans
  +## Updates
  -The following is a list of improvements to this pipeline that are in progress:
  -
  -* *Improved performance* - Work is being done to ensure TensorFlow Lite with
  - TensorFlow ops nicely cooperates with hardware accelerated delegates, for
  - example, NNAPI and GPU delegates.
  +* Version 2.5 (not yet officially released)
  + - You can apply an optimization known as
  + [post training quantization](../performance/post_training_quantization.md)
  +* Version 2.4
  + - Compatibility with hardware accelerated delegates has improved
  