Add serialization format to config.json

[merveenoyan]

We should add which format model was serialized with in config.json so that we could update the example snippet the users can follow both in model card and 🤗Hub repository.

[adrinjalali]

What would the API look like?

[merveenoyan]

@adrinjalali given we initialize the repository after model is saved, either hub_utils.init() should infer the model type (maybe try to call a skops model-specific method) without user entering it or we could put a parameter to it, saying
hub_utils.init(..., skops_format = True) and set it to True by default. Not sure if it's the best though.

[merveenoyan]

@adrinjalali @BenjaminBossan WDYT of this?

[BenjaminBossan]

I don't have a preference, whatever you think works best. The only thing I'd avoid is:

hub_utils.init(..., skops_format = True)

because we might have more formats in the future than pickle vs skops, e.g. ONNX. So if we want to pass it explicitly, it should be something like

hub_utils.init(..., save_format=X)

where X is "pickle" or "skops" for the time being.

[adrinjalali]

We can also have the default value of the arg to be auto, and do this mapping from extension to format:

• .skops -> skops
• .pkl, .pickle, .joblib -> pickle

[BenjaminBossan]

@merveenoyan this is resolved via #242 right?

[adrinjalali]

Yep.