Update actions/setup-node action to v6

Author: renovate[bot]

.github/workflows/deploy-theme.yml

@@ -11,7 +11,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Use Node.js
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@v6
         with:
           node-version: '18.x'
           cache: 'npm'