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

Author: renovate[bot]

.github/workflows/gh-pages.yml

@@ -14,7 +14,7 @@ jobs:
         uses: pnpm/action-setup@v4.1.0
 
       - name: Setup Node
-        uses: actions/setup-node@v4
+        uses: actions/setup-node@v6
         with:
           node-version-file: .node-version
           cache: pnpm