amending azurerm provider block to fix this exmaple

quickstart/201-aks-acr-identity/main.tf

@@ -8,6 +8,10 @@ terraform {
   }
 }
 
+provider "azurerm" {
+  features {}
+}
+
 # Reference to the current subscription.  Used when creating role assignments
 data "azurerm_subscription" "current" {}