Bumps [notebook](https://github.com/jupyter/jupyterhub) from 6.1.5 to 6.4.1.
- [Release notes](https://github.com/jupyter/jupyterhub/releases)
- [Changelog](https://github.com/jupyterhub/jupyterhub/blob/main/CHECKLIST-Release.md)
- [Commits](https://github.com/jupyter/jupyterhub/commits)

---
updated-dependencies:
- dependency-name: notebook
  dependency-type: direct:production
...
Signed-off-by: dependabot[bot] <support@github.com>