VPC module in README is very out of date

[rsmith013]

Version 5.1.1 is now available, updating to this solves an unexpected attribute error but the outputs have changed.

module "vpc" {
source  = "terraform-aws-modules/vpc/aws"
version = "5.1.1"

The output: module.vpc.vpc_cidr_blocks no longer exists and should be replaced with [module.vpc.vpc_cidr_block]

[mSounak]

I have created a PR for it #75