ci: fix checkout submodules

Signed-off-by: Tianling Shen <[email protected]>

.github/workflows/pages.yml

@@ -4,7 +4,8 @@ name: Deploy static content to Pages
 on:
   # Runs on pushes targeting the default branch
   push:
-    branches: ["master"]
+    branches:
+      - 'master'
 
   # Allows you to run this workflow manually from the Actions tab
   workflow_dispatch:
@@ -18,7 +19,7 @@ permissions:
 # Allow only one concurrent deployment, skipping runs queued between the run in-progress and latest queued.
 # However, do NOT cancel in-progress runs as we want to allow these production deployments to complete.
 concurrency:
-  group: "pages"
+  group: 'pages'
   cancel-in-progress: false
 
 jobs:
@@ -31,6 +32,8 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+        with:
+          submodules: 'recursive'
       - name: Setup Pages
         uses: actions/configure-pages@v5
       - name: Upload artifact