chore: update actions/setup-node action to v6

Author: renovate[bot]

.github/workflows/CI.yml

@@ -15,7 +15,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v5
       - name: Use Node.js
-        uses: actions/setup-node@v5
+        uses: actions/setup-node@v6
         with:
           node-version: ${{ matrix.node-version }}
           cache: 'npm'