🌱 Describe your Feature Request

Support Path (from pathlib) as type of argument model

https://github.com/onnx/onnx-coreml/blob/7a630c113b27c8cc1a83412ce1dbfda77f9f8422/onnx_coreml/converter.py#L447

convert doesn't support Path as type of argument model
but onnx.load supports Path

Use cases

from pathlib import Path
model_path = Path("path/to/onnx")
convert(model_p

Problem description

This is a request for a new feature on CI testing.

We would like to have a larger coverage for converter CI tests.
You may refer here https://github.com/microsoft/hummingbird/tree/master/tests for traditional ML -> {PyTorch, ONNX} first.

Other Information

Roadmap (you may change this as you prefer)