chore(deps): update actions/setup-node action to v6

Author: renovate[bot]

.github/workflows/build-antora.yml

@@ -48,7 +48,7 @@ jobs:
         uses: actions/checkout@v6
 
       - name: Setup Node.js
-        uses: actions/setup-node@v5
+        uses: actions/setup-node@v6
         with:
           node-version: ${{ inputs.node-version }}