Ask HN: How do you push config to microservices

Let's say you have dozens of microservices that live in their own code repositories with config to deploy them to something like AWS. how do you manage boilerplate updates to all of them?

Current process is a template repository that gets checked out for new services, however updates to config are made manually to each repo, or copy/pasting boilerplate (which can create havoc if there's an error in the copy/paste)