Update actions/setup-node action to v6

Author: renovate[bot]

.github/workflows/website.yml

@@ -236,7 +236,7 @@ jobs:
       uses: actions/checkout@v7
 
     - name: Set up Node.js
-      uses: actions/setup-node@v4
+      uses: actions/setup-node@v6
       with:
         node-version: 20