ingress-nginx: Upgrade to 0.19.0

Upstream Changes:

-   ingress-nginx 0.19.0 (https://github.com/kubernetes/ingress-nginx/releases/tag/nginx-0.19.0)

Our Changes:

-   Sync templates with upstream changes

roles/kubernetes-apps/ingress_controller/ingress_nginx/templates/svc-default-backend.yml.j2

@@ -5,10 +5,11 @@ metadata:
   name: default-backend
   namespace: {{ ingress_nginx_namespace }}
   labels:
-    k8s-app: default-backend
+    app.kubernetes.io/name: default-backend
+    app.kubernetes.io/part-of: ingress-nginx
 spec:
   ports:
     - port: 80
       targetPort: 8080
   selector:
-    k8s-app: default-backend
+    app.kubernetes.io/name: default-backend