Use pause image from new source.

Signed-off-by: Lantao Liu <lantaol@google.com>

contrib/ansible/cri-containerd.yaml

@@ -56,6 +56,6 @@
     # TODO This needs to be removed once we have consistent concurrent pull results
     - name: "Pre-pull pause container image"
       shell: |
-        /usr/local/bin/ctr pull gcr.io/google_containers/pause:3.1
+        /usr/local/bin/ctr pull k8s.gcr.io/pause:3.1
         /usr/local/bin/crictl --runtime-endpoint /run/containerd/containerd.sock \
-        pull gcr.io/google_containers/pause:3.1
+        pull k8s.gcr.io/pause:3.1