Fixes failed export to ONNX when input w/h is dynamic

[matthill]

This change fixes a failed export to ONNX when using dynamic values for w/h input. Example export code below:

input_shape = 1, 3, 640, 640
feat = torch.randn(input_shape)

input_names = ["input"]

torch.onnx.export(model, feat, 'model.onnx',
                  input_names=input_names,
                  dynamic_axes={'input': {2: 'width', 3: 'height'}},
                  verbose=True, opset_version=18)

[github-actions]

This PR is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 15 days.

[github-actions]

This PR was closed because it has been stalled for 15 days with no activity.