fix tflint errors in example

Author: briskt

example/providers.tf

@@ -1,3 +1,14 @@
+terraform {
+  required_version = ">= 1.0"
+
+  required_providers {
+    aws = {
+      source  = "hashicorp/aws"
+      version = "~> 5.0"
+    }
+  }
+}
+
 provider "aws" {
   region = var.aws_region
 

example/variables.tf

@@ -1,3 +1,4 @@
 variable "aws_region" {
+  type    = string
   default = "us-east-1"
 }