Reducing time wait for ingress controller shutdown

According to https://medium.com/codecademy-engineering/kubernetes-nginx-and-zero-downtime-in-production-2c910c6a5ed8 95 seconds seems like too much for ingress controller preStop shutdown.

deployment/helm/ditto/templates/nginx-ingress.yaml

@@ -646,7 +646,7 @@ spec:
         lifecycle:
           preStop:
             exec:
-              command: ["sleep", "95"]
+              command: ["sleep", "{{ .Values.ingress.controller.preStopWait }}"]
         env:
         - name: POD_NAME
           valueFrom:

deployment/helm/ditto/values.yaml

@@ -206,6 +206,10 @@ ingress:
     #  of its containers crashing, for it to be considered available
     #  ref: https://kubernetes.io/docs/concepts/workloads/controllers/deployment/#min-ready-seconds
     minReadySeconds: 10
+    # as NGINX Ingress Controller on its pod shutdown tends to interrupt connections, we need to include 
+    # some wait time so that existing connections are fully handled before the pod is really shut down. 
+    # ref: https://medium.com/codecademy-engineering/kubernetes-nginx-and-zero-downtime-in-production-2c910c6a5ed8
+    preStopWait: 15
     # specify how many old ReplicaSets for ingress controller deployment will be retained
     # ref: https://kubernetes.io/docs/concepts/workloads/controllers/deployment/#clean-up-policy
     revisionHistoryLimit: 5