Add option to enforce storing changelogs in project root for mono repositories

[NiklasRosenstein]

Eg. for https://github.com/kraken-build/kraken I'd like that you can't accidentally add a changelog to the subdirectories. What could be even nicer: Instead of denying adding the changelog entry when running from inside the subdirectory, it would add the changelog to the root with the component field set to the subdirectory name.