Bump jupyterhub/jupyterhub from 3.1.1 to 4.0.2

Bumps jupyterhub/jupyterhub from 3.1.1 to 4.0.2.

---
updated-dependencies:
- dependency-name: jupyterhub/jupyterhub
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Dockerfile

@@ -1,4 +1,4 @@
-FROM jupyterhub/jupyterhub:3.1.1 as base-image
+FROM jupyterhub/jupyterhub:4.0.2 as base-image
 
 # Update system packages
 COPY scripts/install-base-packages.sh .