added terraform for create a virtual network with two subnets quickstart in virtual network docset

quickstart/101-virtual-network-create-two-subnets/providers.tf

@@ -0,0 +1,16 @@
+terraform {
+  required_providers {
+    azurerm = {
+      source  = "hashicorp/azurerm"
+      version = "~>3.0"
+    }
+    random = {
+      source  = "hashicorp/random"
+      version = "~>3.0"
+    }
+  }
+}
+
+provider "azurerm" {
+  features {}
+}