is the install.py script still relevant given data_files support in `setup.py`?

Hi there,

Thank you for creating this reference custom kernel!

Through some investigations, I thought that the recommended path is to use data_files support in `setup.py`, as opposed to manually moving files into the `share/jupyter/kernels/` directory. I also noticed that the `kernel.json` pattern (mentioned in https://jupyter-client.readthedocs.io/en/stable/kernels.html) is not used here.

Is this current repo not up to date with the most recent ipykernel developments, or did I mis-read some instructions?

Thanks so much for the help!