message: Add TF Probability mailing list to community pages.
diff: @@ -32,6 +32,8 @@ These projects inside the TensorFlow GitHub organization have lists dedicated to
  and peer support for TensorFlow.js.
  * [tflite](https://groups.google.com/a/tensorflow.org/d/forum/tflite) - Discussion and
  peer support for TensorFlow Lite.
  +* [tfprobability](https://groups.google.com/a/tensorflow.org/d/forum/tfprobability) - Discussion and
  + peer support for TensorFlow Probability.
  * [tpu-users](https://groups.google.com/a/tensorflow.org/d/forum/tpu-users) - Community discussion
  and support for TPU users.
  