--store is broken (I think) as a subschema now references another schema (base.json for poetry’s license). I think this is a good opportunity to add the ability to load --extra schemas that can be referenced and --store will load them and the new api would have a way to provide them.

We've got our first nested schema, so I'll need to work on this: henryiii/validate-pyproject-schema-store#90

(that's also what's breaking our tests)