Added Azure CLI requirement

Author: ggailey777

articles/azure-functions/functions-create-first-function-terraform.md

@@ -30,6 +30,7 @@ In this quickstart, you use Terraform to create a function app in a Flex Consump
 
 - Create an Azure account with an active subscription. You can [create an account for free](https://azure.microsoft.com/free/?WT.mc_id=A261C142F).
 - [Install and configure Terraform](/azure/developer/terraform/quickstart-configure).
+- [Install the Azure CLI](/cli/azure/install-azure-cli) to obtain the subscription ID or run in [Azure Cloud Shell](/azure/cloud-shell/overview).
 
 ## Implement the Terraform code