fix: use base cuda 11 image for test dlc gpu image

Author: Dan Choi

test/container/1.6.0/Dockerfile.dlc.gpu

@@ -1,5 +1,5 @@
 ARG region
-from 763104351884.dkr.ecr.$region.amazonaws.com/pytorch-training:1.6.0-gpu-py36-cu101-ubuntu16.04
+from 763104351884.dkr.ecr.$region.amazonaws.com/pytorch-training:1.6.0-gpu-py36-cu110-ubuntu16.04
 
 # TODO: Remove once the 1.6.0-gpu-py3 DLC image installs mpi4py
 RUN pip3 install mpi4py==3.0.3