updated build.sh for ppc

Author: sandeepgupta12

.ci/docker/manywheel/Dockerfile_ppc64le

@@ -38,7 +38,11 @@ RUN apt install -y \
   liblapack-dev \
   libatlas-base-dev
 
-RUN apt install -y linux-headers-$(uname -r) || apt install -y linux-headers-generic
+# Handle linux-headers installation gracefully
+RUN apt-get update && \
+    (apt install -y linux-headers-$(uname -r) || apt install -y linux-headers-generic || \
+    echo "Skipping linux-headers installation as it is not critical") && \
+    apt-get clean && rm -rf /var/lib/apt/lists/*
 
 # git236+ would refuse to run git commands in repos owned by other users
 # Which causes version check to fail, as pytorch repo is bind-mounted into the image