v0.23.0

Update vpc-endpoints submodule docs, examples/vpc-endpoints use null label @korenyoni (#83)

what

• Update docs for vpc-endpoints submodule using terraform-docs
• Update examples/vpc-endpoints to not manually override tags for aws_security_group resources in examples/vpc-endpoints — insantiate a new null label module and supply it attributes.

why

• The vpc-endpoints submodule generated docs are out-of-date.
• The use of tag overrides in examples/vpc-endpoints is not in line with CloudPosse style.

references

• #82