Scalars have caused some issues with onnx import

[loloxwg]

Describe the bug
Scalars have caused some issues with onnx import..in this case it looks like the constant node import does not correctly handle them.

To Reproduce

Steps to reproduce the behavior:

1. Go to https://huggingface.co/AndrewOgn/resnet_onnx/tree/main down the onnx file
2. Run code

    // Generate the model code from the ONNX file.

    // If not embedded-model, then model is loaded from the file system (default).
    ModelGen::new()
        .input("src/model/resnet_model.onnx")
        .out_dir("model/")
        .development(true)
        .run_from_script();
    
}

Expected behavior

Generage a model.rs file

Screenshots

Desktop (please complete the following information):

• OS: Mac OS m1
• Browser Chrome
• Version da8de56

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context