diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 2bff6d7..e6adf62 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -13,6 +13,8 @@ jobs:
       runs-on: ubuntu-20.04
       steps:
         - uses: actions/checkout@v2
+          with:
+            submodules: recursive
         - uses: actions/setup-python@v2
           with:
             python-version: '3.8'