Update README.md

Author: alexellis

README.md

@@ -1,2 +1,26 @@
 # setup-k3sup
+
 Setup a k3s cluster with k3sup
+
+Usage:
+
+```yaml
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Kubernetes
+        uses: self-actuated/setup-k3sup@master
+        with:
+          cache: 'true'
+          
+      - name: Get nodes
+        run: |
+          export KUBECONFIG=~/.kube/config
+          kubectl get nodes -o wide
+```
+
+## Todo
+
+* Add input for `--k3s-channel`
+* Add input for skipping Traefik
+