Handle AWS region changes easier

There's a bunch of AWS plugins that need to have the correct regions encoded or else they can't connect. Thus they all have a similar requirement, that when a new region is added, they need to be updated accordingly. eg;
https://github.com/logstash-plugins/logstash-output-s3
https://github.com/logstash-plugins/logstash-input-s3
https://github.com/logstash-plugins/logstash-mixin-aws

I was wondering if perhaps we might not have a smarter way to do this, rather than rely on individual PRs?