[ANN] repo2docker upgrading to JupyterLab 4

repo2docker will be soon upgrading from JupyterLab 3 (has reached end of maintenance this month) to JupyterLab 4.

Affected users:

There will be another more significant upgrade to Jupyter Server 2 and notebook 7, as well, after this has completed: Update to JupyterLab 4 and Notebook 7 by jtpio · Pull Request #1302 · jupyterhub/repo2docker · GitHub