Support Upsample and Deconvolution operators in mx2onnx

How to support Upsample and Deconvolutioon operators in mx2onnx. Thanks

@sanyuan Thanks for trying out MXNet to ONNX exporter. We don’t have support for all the operators yet.
Please check this PR for Deconvolution operator: Need to address the comments provided and Deconvolution operator should be good to go.
Similarly for upsample, you will need to add mapping from to

We will be expanding support for more operators, meanwhile you are also welcome to contribute to mx2onnx by adding the support for these operators. :slight_smile: