setuptools should normally be installed as a dependency of babel, itself a dependency of jupyterlab_server.
Nevertheless, it seems that some version of babel do not have this explicit dependency (e.g. babel==2.10), which can lead to instable installation of nbgrader.
Fix https://github.com/jupyter/nbgrader/issues/1838
This PR adds a dependency to setuptools.
setuptools should normally be installed as a dependency of babel, itself a dependency of jupyterlab_server.
Nevertheless, it seems that some version of babel do not have this explicit dependency (e.g.
babel==2.10
), which can lead to instable installation of nbgrader.