Update conda package

The `conda` package supports only `python` <= 3.8. In order to update, afaik, the upstream path starts from `itk`.

Please check and accept https://github.com/conda-forge/itk-feedstock/pull/36 so that the work on the `itkwidgets` update can continue.

Otherwise, could you please provide a roadmap for updating the `conda` option.

Thanks