Add PY2 support

Author: mvsusp

docker/1.1.0/final/Dockerfile.cpu

@@ -1,4 +1,5 @@
-FROM pytorch-base:1.1.0-cpu-py3
+ARG py_version
+FROM pytorch-base:1.1.0-cpu-py$py_version
 
 LABEL com.amazonaws.sagemaker.capabilities.accept-bind-to-port=true
 

docker/1.1.0/final/Dockerfile.gpu

@@ -1,4 +1,5 @@
-FROM pytorch-base:1.1.0-gpu-py3
+ARG py_version
+FROM pytorch-base:1.1.0-gpu-py$py_version
 
 LABEL com.amazonaws.sagemaker.capabilities.accept-bind-to-port=true