ingress-nginx: Upgrade to 0.20.0 (#3565)

Upstream Changes:

-   ingress-nginx 0.20.0 (https://github.com/kubernetes/ingress-nginx/releases/tag/nginx-0.20.0)

Our Changes:

-   Sync templates with upstream changes

roles/kubernetes-apps/ingress_controller/ingress_nginx/templates/ds-ingress-nginx-controller.yml.j2

@@ -18,8 +18,8 @@ spec:
         app.kubernetes.io/name: ingress-nginx
         app.kubernetes.io/part-of: ingress-nginx
       annotations:
-        prometheus.io/port: '10254'
-        prometheus.io/scrape: 'true'
+        prometheus.io/port: "10254"
+        prometheus.io/scrape: "true"
     spec:
       serviceAccountName: ingress-nginx
 {% if ingress_nginx_host_network %}

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

@@ -13,3 +13,4 @@ spec:
       targetPort: 8080
   selector:
     app.kubernetes.io/name: default-backend
+    app.kubernetes.io/part-of: ingress-nginx