Also update matching README.md example

Author: consideRatio

README.md

@@ -41,7 +41,7 @@ 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