Add readiness probe to dns-autoscaler (#6382)

roles/kubernetes-apps/ansible/templates/dns-autoscaler.yml.j2

@@ -65,6 +65,11 @@ spec:
           requests:
             cpu: {{ dns_autoscaler_cpu_requests }}
             memory: {{ dns_autoscaler_memory_requests }}
+        readinessProbe:
+          httpGet:
+            path: /healthz
+            port: 8080
+            scheme: HTTP
         command:
         - /cluster-proportional-autoscaler
         - --namespace=kube-system