Generic types cannot be deserialized

[SusanneLindgren]

If a value has type dict, it can be deserialized, but not if it has a more specific type like dict[str, str]; then you get an exception:

jsons.exceptions.DeserializationError: Could not deserialize value "{'foo': 'bar'}" into "dict". isinstance() argument 2 cannot be a parameterized generic

Example code:

import jsons
from dataclasses import dataclass

@dataclass
class Test:
    value: dict[str, str]  # but "dict" works

t = Test({"foo": "bar"})
dumped = jsons.dump(t)
reloaded = jsons.load(dumped, Test)
print(reloaded.value)

Suggested fix: change default_union_deserializer in jsons/deserializers/default_union.py from return load(obj, sub_type, **kwargs) to

            try:
                origin_type = sub_type.__origin__
            except AttributeError:
                origin_type = sub_type
            return load(obj, origin_type, **kwargs)

A similar fix would have to be done for lists.