deploy: use cluster registry pull secret

deploy/k8s/10-deployment.yaml

@@ -34,6 +34,8 @@ spec:
         reloader.stakater.com/auto: "true"
     spec:
       serviceAccountName: fancy-dns
+      imagePullSecrets:
+        - name: reg-k6n
       # No hostNetwork. The server does not set SO_REUSEPORT, so a second
       # host-network pod would fail to bind :53 and crash-loop; the ports are
       # served by a LoadBalancer Service instead (see 20-service.yaml).