Update dockerfile to use cuda image

Dockerfile

@@ -1,4 +1,4 @@
-from ubuntu:20.04
+from nvidia/cuda:11.3.1-runtime-ubuntu20.04
 
 ENV GRADIO_SERVER_NAME=0.0.0.0
 
@@ -13,7 +13,7 @@ RUN apt update && \
     rm -rf /var/lib/apt/lists
 
 RUN python3 -m pip install --no-cache-dir --upgrade pip && \
-    python3 -m pip install --no-cache-dir --extra-index-url https://download.pytorch.org/whl/cpu \
+    python3 -m pip install --no-cache-dir --extra-index-url https://download.pytorch.org/whl/cu113 \
     torch \
     torchvision \
     torchaudio