updated dockerfile

Author: sandeepgupta12

.github/workflows/Dockerfile.ppc64le

@@ -13,7 +13,7 @@ RUN ln -sf /usr/bin/python3 /usr/bin/python && \
     ln -sf /usr/bin/pip3 /usr/bin/pip
 
 # Install Python packages via pip
-RUN pip install wheel setuptools
+RUN pip install wheel setuptools pyyaml
 
 # Copy the PyTorch source code into the container
 COPY . /workspace/pytorch