fix test input

Author: Nuru

examples/existing-ips/main.tf

@@ -26,7 +26,7 @@ module "subnets" {
   availability_zones   = var.availability_zones
   vpc_id               = module.vpc.vpc_id
   igw_id               = [module.vpc.igw_id]
-  cidr_block           = [module.vpc.vpc_cidr_block]
+  ipv4_cidr_block      = [module.vpc.vpc_cidr_block]
   nat_elastic_ips      = aws_eip.nat_ips.*.public_ip
   nat_gateway_enabled  = true
   nat_instance_enabled = false