False positive when object becomes alias to object of the same type

[pawamoy]

Describe the bug
Following #145, replacing a function with an alias to a function should not be detected as a breaking change.
src/duty/callables/__init__.py:31: lazy: Public object points to a different kind of object: function -> alias

Expected behavior
If the alias points to another package, we will need to resolve it (external=True when resolving?).

[pawamoy]

We now follow aliases when checking API breaking changes, so I'll close this for now, and it could be re-opened as a feature request to automatically load external modules when an alias cannot be resolved, to make sure there's a breaking change or not. The alternative is to just output a warning: "can't resolve alias, possible breaking change".