build: Use deploy key for build-demos

Author: regeter

.github/workflows/build-demos.yml

@@ -20,8 +20,13 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
-      - uses: actions/setup-node@v3
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          ssh-key: ${{ secrets.DEPLOY_KEY }}
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v3
         with:
           node-version: '16'
           cache: 'npm'