[GitHub Actions] Clone submodules

Author: ShonP40

.github/workflows/build.yml

@@ -7,6 +7,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v3
+        with:
+          submodules: recursive
       - name: Install Java 8
         uses: actions/setup-java@v3
         with: