Update actions/setup-node action to v6

Author: renovate[bot]

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Use Node.js
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version: ${{ matrix.node-version }}