Document how to structure project so that Dependabot can access Changelog

Dependabot is so wide-spread that it makes sense for projects to structure them in a way to make it easy for dependabot to pick up information. However, I don't know how to make dependabot pick up the changelog in the best way.

A short guide how to structure a CHANGELOG file to get nice dependabot messages would be cool :pray:

Indicators that this might be helpful:

* https://github.com/eslint/eslint/issues/14708
* https://github.com/appsignal/appsignal-nodejs/issues/564
* https://github.com/diffplug/spotless/issues/1048
* https://github.com/golangci/golangci-lint/issues/1270

It would be extremely awesome if there was a web-tool to check what dependabot picks up ... but just some docs would already help a lot.