build(deps): bump jupyterhub-kubespawner in /images/hub

Bumps [jupyterhub-kubespawner](https://github.com/jupyterhub/kubespawner) from 3.0.2 to 4.0.0.
- [Release notes](https://github.com/jupyterhub/kubespawner/releases)
- [Changelog](https://github.com/jupyterhub/kubespawner/blob/main/RELEASE.md)
- [Commits](jupyterhub/kubespawner@3.0.2...4.0.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

images/hub/requirements.txt

@@ -87,7 +87,7 @@ jupyterhub-hmacauthenticator==1.0
     # via -r requirements.in
 jupyterhub-idle-culler==1.2.1
     # via -r requirements.in
-jupyterhub-kubespawner==3.0.2
+jupyterhub-kubespawner==4.0.0
     # via -r requirements.in
 jupyterhub-ldapauthenticator==1.3.2
     # via -r requirements.in