Update actions/setup-node action to v6

Author: renovate[bot]

.github/workflows/jekyll.yml

@@ -23,7 +23,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
       - name: Setup node
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: 22
       - name: Setup NPM dependencies