Are there plans for Travis running the Composer stuff automatically?

I'd say make the adjustment in a branch, push it, and if Travis doesn't break we merge it in - just to be future prove

Are there plans for Travis running the Composer stuff automatically?

But it runs automatically or I am wrong?

You are wrong I guess. Composer is installed, but you have to run (and update) it on your own.

The article says that Travis will do this in the future, but the documentation does not contain any information about it (yet).