Logging is too chatty at WARN level

[nikita2206]

Describe the bug We're currently getting a WARN-level log line when one of the Maven modules doesn't have a tests directory.

The code responsible for this: https://github.com/spotify/fmt-maven-plugin/blob/1cf19c0cb5a88272a50bfafed8935c79b946c62f/src/main/java/com/spotify/fmt/AbstractFMT.java#L104-L108

https://github.com/spotify/fmt-maven-plugin/blob/1cf19c0cb5a88272a50bfafed8935c79b946c62f/src/main/java/com/spotify/fmt/AbstractFMT.java#L184-L198

It looks like it will WARN you of a missing directory even if you explicitly excluded that directory from being checked (even if it does in fact exist).

To me it feels like this is the kind of information that deserves to be logged but at a INFO level, otherwise it leads to 'warning fatigue' because most of the time this isn't something that people will act on and it's also not possible to disable.