Modifying providers.tf as provider blocks can't contain vars

Author: TomArcherMsft

quickstart/201-k8s-cluster-with-aks-applicationgateway-ingress/providers.tf

@@ -9,8 +9,8 @@ terraform {
     }
   }
   backend "azurerm" {
-    resource_group_name = var.resource_group_name
-    storage_account_name = var.storage_account_name
+    resource_group_name = <storage_account_resource_group>
+    storage_account_name = <storage_account_name>
     container_name = "tfstate"
     key = "codelab.microsoft.tfstate"
   }