Terraform azurerm 2.x Error: "features": required field is not set

OK, running terraform in debug mode showed it was at the provider level that the error was being thrown.

It's not listed in the 2.0 upgrade guide but if you look at the provider docs it now shows a features{} block.

So at a minimum the provider now needs to look like:

provider "azurerm" {
   features {}
}