AETHER-2529 aether-roc-umbrella 3 prometheus and 2 prom-label-proxy

Change-Id: I01c4f60bfa265156cda88ffa1e8b73c5232c22d8
diff --git a/aether-roc-umbrella/templates/alertmanager-configmap.yaml b/aether-roc-umbrella/templates/alertmanager-configmap.yaml
index cbbcfe3..703c11a 100644
--- a/aether-roc-umbrella/templates/alertmanager-configmap.yaml
+++ b/aether-roc-umbrella/templates/alertmanager-configmap.yaml
@@ -15,7 +15,7 @@
     receivers:
       - name: default-receiver
         webhook_configs:
-        - url: {{ .Values.prometheus.alertmanager.webhook_url }}
+        - url: {{ index .Values "prometheus-acc" "alertmanager" "webhook_url" }}
 
     route:
       group_wait: 10s