updated manywheel docker file

Author: sandeepgupta12

.ci/docker/manywheel/Dockerfile_ppc64le

@@ -12,7 +12,9 @@ RUN dnf install -y \
 RUN ln -sf /usr/bin/python3 /usr/bin/python && \
     ln -sf /usr/bin/pip3 /usr/bin/pip
 
-COPY /pytorch/.ci/docker/manywheel/requirements.txt .
+RUN ln -s /pytorch/requirements.txt /pytorch/.ci/docker/manywheel/requirements.txt
+
+COPY requirements.txt .
 # Install Python packages via pip
 RUN pip install wheel setuptools pyyaml typing_extensions expecttest