Revert "documentation: removing mention of TF 2.4 from SM distributed model parallel docs"

This reverts commit 8377b86.

Author: Talia Chopra

doc/api/training/smd_model_parallel_release_notes/smd_model_parallel_change_log.md

@@ -17,6 +17,10 @@
 
 - Adds support for `_register_comm_hook` (PyTorch 1.7 only) which will register the callable as a communication hook for DDP. NOTE: Like in DDP, this is an experimental API and subject to change.
 
+### Tensorflow
+
+- Adds support for Tensorflow 2.4
+
 ## Bug Fixes
 
 ### PyTorch

doc/api/training/smp_versions/v1.2.0/smd_model_parallel_tensorflow.rst

@@ -1,7 +1,7 @@
 TensorFlow API
 ==============
 
-**Supported version: 2.3**
+**Supported version: 2.4, 2.3**
 
 **Important**: This API document assumes you use the following import statement in your training scripts.