Listing lab/notebook extensions shows red X

[bollwyvl]

It looks like there is a bad pin somewhere... it probably works, but when things like this are broken, it causes confusion for maintainers.

Operating system

Linux

• CI for conda-forge/nbgrader-feedstock#64

nbgrader --version

0.9.0

jupyterhub --version (if used with JupyterHub)

n/a

jupyter notebook --version

n/a

Expected behavior

+ jupyter labextension list
        nbgrader v0.9.0 enabled  OK (python, nbgrader)

Actual behavior

+ jupyter labextension list
JupyterLab v4.0.5 $PREFIX/share/jupyter/labextensions
        nbgrader v0.9.0 enabled  X (python, nbgrader)

Steps to reproduce the behavior

+ jupyter labextension list

[brichet]

Thanks @bollwyvl for reporting this and updating the conda-forge receipe.
I opened #1827 to fix the compatibility error, and to add a test on it.