Fix unknown field error in ModelSerializer

[aminiun]

My real scenario is when I include some fields that does not exists in the model. For example assume that I have a model called Store, which does not have token field.

In this example, if I have a ModelSerializer like this:

class StoreSerializer(ModelSerializer):
    ...
    class Meta:
        fields = (
            ...
            "token"
        )

Then I will face an exception like: 'Field name `token` is not valid for model `Store`.' .

This can really be a headache, when I have multiple serializers for Store model. So I suggest to simply have the model path, to be more clear about which serializer is corrupt.

[aminiun]

@auvipy I couldn't figure out why CI / Python 3.9 job failed. Isn't it a problem with CI ? Or my PR made this happen

[auvipy]

that is unrelated with your PR

[aminiun]

@auvipy Any plan for this PR ?

[auvipy]

would be a good usability improvement