fix example (#178)

quickstart/201-function-app-key-vault-ref/providers.tf

@@ -1,18 +1,23 @@
 terraform {
-  required_version = ">=1.0"
+  required_version = ">= 1.0"
 
   required_providers {
     azurerm = {
       source  = "hashicorp/azurerm"
-      version = "~>3.8"
+      version = ">= 3.0, < 4.0"
+    }
+    random = {
+      source  = "hashicorp/random"
+      version = ">= 3.0"
     }
   }
 }
 provider "azurerm" {
   features {
     key_vault {
-      purge_soft_delete_on_destroy    = true
-      recover_soft_deleted_key_vaults = true
+      recover_soft_deleted_key_vaults    = false
+      purge_soft_delete_on_destroy       = false
+      purge_soft_deleted_keys_on_destroy = false
     }
   }
 }