[BUG] nullable TF variable causes warning to be logged

[szesch]

Describe the bug
A warning is logged when a TF variable is encountered with nullable set. nullable is a legitimate argument for a variable. https://developer.hashicorp.com/terraform/language/values/variables#disallowing-null-input-values

Unsupported argument; An argument named "nullable" is not expected here

How you're running Regula

• I'm using Regula v3.0.0 as a CLI tool and my Terraform source code as an input:

regula run -f table -v

Operating System

Ubuntu 22.04

IaC Configuration

variable "foobar" {
  type        = string
  default     = null
  nullable    = true
}