Changes update strategy from OnDelete to automatic

To see this in action, with no other changes:
kubectl -n kafka patch statefulset kafka --type='json' -p='[{"op": "replace", "path": "/spec/updateStrategy/type", "value": "RollingUpdate"}]'

Author: solsson

50kafka.yml

@@ -6,6 +6,8 @@ metadata:
 spec:
   serviceName: "broker"
   replicas: 3
+  updateStrategy:
+    type: RollingUpdate
   template:
     metadata:
       labels: