Deprecated functionalities in jupyterlab_packaging

[Carreau]

$ jupyter labextension develop --overwrite .
setup.py:35: DeprecatedWarning: create_cmdclass is deprecated as of 0.8 and will be removed in 1.0. "
Use `wrap_installers` to handle prebuild steps in cmdclass.
Use `get_data_files` to handle data files.
Use `include_package_data=True` and `MANIFEST.in` for package data.

  "jsdeps", package_data_spec=package_data_spec, data_files_spec=data_files_spec
setup.py:39: DeprecatedWarning: install_npm is deprecated as of 0.8 and will be removed in 1.0. Use `npm_builder` and `wrap_installers`
  jupyter_packaging.install_npm(HERE, build_cmd="build:prod", npm=["jlpm"]),

Those should likely be updated.