GitLab

Bumps [notebook](https://github.com/jupyter/jupyterhub) from 6.1.4 to 6.1.5.
- [Release notes](https://github.com/jupyter/jupyterhub/releases)
- [Changelog](https://github.com/jupyterhub/jupyterhub/blob/master/CHECKLIST-Release.md)
- [Commits](https://github.com/jupyter/jupyterhub/commits

)
Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>