ci: checkout codes before executing other steps

Author: siujamo

.github/workflows/github-pages.yml

@@ -13,6 +13,9 @@ jobs:
       contents: read
 
     steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
       - name: Setup Node.js environment
         uses: actions/setup-node@v3.9.1
         with: