perf(external-dns): trigger DNS update based on k8s events

- Reduce polling from 1m (default) to 5m
- More responsive updates

system/external-dns/values.yaml

@@ -9,7 +9,8 @@ external-dns:
           key: value
   extraArgs:
     - --annotation-filter=external-dns.alpha.kubernetes.io/exclude notin (true)
-
+  interval: 5m
+  triggerLoopOnEvent: true
   metrics:
     enabled: true
     serviceMonitor: