replace local by var ref

Author: npalm

examples/prebuilt/vpc.tf

@@ -5,7 +5,7 @@ module "vpc" {
   name = "vpc-${local.environment}"
   cidr = "10.0.0.0/16"
 
-  azs             = ["${local.aws_region}a", "${local.aws_region}b", "${local.aws_region}c"]
+  azs             = ["${var.aws_region}a", "${var.aws_region}b", "${var.aws_region}c"]
   private_subnets = ["10.0.1.0/24", "10.0.2.0/24", "10.0.3.0/24"]
   public_subnets  = ["10.0.101.0/24", "10.0.102.0/24", "10.0.103.0/24"]