Use conda_forge vega_datasets instead of pypi vega-datasets
Use conda_forge vega_datasets instead of pypi vega-datasets

Co-authored-by: Jeremy Tuloup <89dba748b4dff178851bd6b00abd7acb38c96b59@gmail.com>
jupyter/jupyterlab,jupyter/jupyterlab,jupyter/jupyterlab,jupyter/jupyterlab,jupyter/jupyterlab