build(deps): bump jupyterhub/action-k3s-helm from 3 to 4

Bumps [jupyterhub/action-k3s-helm](https://github.com/jupyterhub/action-k3s-helm) from 3 to 4.
- [Release notes](https://github.com/jupyterhub/action-k3s-helm/releases)
- [Changelog](https://github.com/jupyterhub/action-k3s-helm/blob/main/CHANGELOG.md)
- [Commits](v3...v4)

---
updated-dependencies:
- dependency-name: jupyterhub/action-k3s-helm
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/readme_example.yml

@@ -14,7 +14,7 @@ jobs:
     steps:
       # GitHub Action reference: https://github.com/jupyterhub/action-k3s-helm
       - name: Start a local k8s cluster
-        uses: jupyterhub/action-k3s-helm@v3
+        uses: jupyterhub/action-k3s-helm@v4
         with:
           # See available:
           # - k3s release channels at https://github.com/k3s-io/k3s/blob/HEAD/channel.yaml