Error in functionapp module

In the terraform module, [functionapp](https://registry.terraform.io/modules/anoff/functionapp/azurerm/0.4.0) referenced from issue
https://github.com/Azure/terraform/issues/16 there seems to be an issue related to the upgrade of terraform 0.11.14 to 0.12.

The following error message is received from the following input in 0.12 and not in 0.11.14

**Error**
```
on .terraform\modules\myfunction\anoff-terraform-azurerm-functionapp-bc17e58\main.tf line 49, in resource "azurerm_function_app" "funcapp":
49: site_config = "${local.site_config}"

An argument named "site_config" is not expected here. Did you mean to define a
block of type "site_config"?
```

**Input**
```
module "myfunction" {
source = "anoff/functionapp/azurerm"
name = "myfunction"
location = "${var.az_region_default}"
plan_type = "consumption"
}
```

Found [this ](https://github.com/terraform-providers/terraform-provider-azurerm/commit/9738a21e588a4a220003e12fb2e72ea19f1138fe)and [this](https://github.com/terraform-providers/terraform-provider-azurerm/pull/3210), which seem related but I'm not quite sure.

Start with the referenced functionapp module's main.tf at line 49 and reproduce the module block shown with Terraform 0.12. Compare the related provider commit and pull request, then confirm the module works with the newer Terraform/provider behavior and that the reported error no longer occurs.

Written by the indexing model from the issue text.