chore: checkout submodules in the CI

Author: hamzaremmal

.github/workflows/build-site.yml

@@ -13,6 +13,8 @@ jobs:
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v4
+        with:
+          submodules: true
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
         with: