Update Ingress-NGINX to 0.21 Release

Updates Ingress-Nginx to use 0.21 release. Also changes name of
the Configuration Map to the one used in Ingress-NGINX repo for
consistency.

deploy/addons/ingress/ingress-configmap.yaml

@@ -19,7 +19,7 @@ data:
   hsts: "false"
 kind: ConfigMap
 metadata:
-  name: nginx-load-balancer-conf
+  name: nginx-configuration
   namespace: kube-system
   labels:
     addonmanager.kubernetes.io/mode: EnsureExists

deploy/addons/ingress/ingress-dp.yaml

@@ -87,7 +87,7 @@ spec:
       serviceAccountName: nginx-ingress
       terminationGracePeriodSeconds: 60
       containers:
-      - image: quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.19.0
+      - image: quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.21.0
         name: nginx-ingress-controller
         imagePullPolicy: IfNotPresent
         readinessProbe:
@@ -122,7 +122,7 @@ spec:
         args:
         - /nginx-ingress-controller
         - --default-backend-service=$(POD_NAMESPACE)/default-http-backend
-        - --configmap=$(POD_NAMESPACE)/nginx-load-balancer-conf
+        - --configmap=$(POD_NAMESPACE)/nginx-configuration
         - --tcp-services-configmap=$(POD_NAMESPACE)/tcp-services
         - --udp-services-configmap=$(POD_NAMESPACE)/udp-services
         - --annotations-prefix=nginx.ingress.kubernetes.io