This example demonstrates how to deploy hub and spoke VPCs, inclusive of enabling DNS-sharing using a manual DNS resolver in the spoke VPC (as opposed to a delegated resolver).
Caveat: Using a manual resolver, as opposed to a delegated resolver requires to ensure that the custom resolver IPs in the hub VPC do not change outside the terraform lifecycle (which should be the case if you follow a proper IaC approach).
Refer to the documentation here if you are new to hub-spoke dns-sharing VPC topology.