Don't search filesystem mounts in docker build step

This fixes the build process failing when building the
image using podman as it gives a permission denied /proc/

Dockerfile

@@ -2,7 +2,7 @@
 FROM ubuntu:jammy-20230308
 # Some tools like yamllint need this
 # Pip needs this as well at the moment to install ansible
-# (and potentially other packages) 
+# (and potentially other packages)
 # See: https://github.com/pypa/pip/issues/10219
 ENV LANG=C.UTF-8 \
     DEBIAN_FRONTEND=noninteractive \
@@ -38,4 +38,4 @@ RUN apt update -q \
     && echo $(curl -L https://dl.k8s.io/release/$KUBE_VERSION/bin/linux/$(dpkg --print-architecture)/kubectl.sha256) /usr/local/bin/kubectl | sha256sum --check \
     && chmod a+x /usr/local/bin/kubectl \
     && rm -rf /var/lib/apt/lists/* /var/log/* \
-    && find / -type d -name '*__pycache__' -prune -exec rm -rf {} \;
+    && find / -mount -type d -name '*__pycache__' -prune -exec rm -rf {} \;