Documentation: SMP API Add 1.6 to supported versions

Author: anirudh2290

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

@@ -6,7 +6,7 @@
 PyTorch API
 ===========
 
-**Supported versions: 1.7.1**
+**Supported versions: 1.7.1, 1.6**
 
 This API document assumes you use the following import statements in your training scripts.
 

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

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