doc: SMDDP 1.2.0 release notes (#2319)

Co-authored-by: Talia <[email protected]>
Co-authored-by: Ahsan Khan <[email protected]>

Author: 3 people

doc/api/training/smd_data_parallel_release_notes/smd_data_parallel_change_log.md

@@ -1,3 +1,16 @@
+# Sagemaker Distributed Data Parallel 1.2.0 Release Notes
+
+* New features
+* Bug Fixes
+
+*New features:*
+
+* Support of [EFA network interface](https://aws.amazon.com/hpc/efa/) for distributed AllReduce. For best performance, it is recommended you use an instance type that supports Amazon Elastic Fabric Adapter (ml.p3dn.24xlarge and ml.p4d.24xlarge) when you train a model using SageMaker distributed data parallel.
+
+*Bug Fixes:*
+
+* Improved performance on single node and small clusters.
+
 # Sagemaker Distributed Data Parallel 1.1.2 Release Notes
 
 * Bug Fixes