Fix Github Actions

Make github actions pull submodules

.github/workflows/main-ci.yml

@@ -9,6 +9,8 @@ jobs:
 
         steps:
             - uses: actions/checkout@v2
+            - name: Checkout submodules
+              run: git submodule update --init --recursive
 
             - name: Set up Java 8
               uses: actions/setup-java@v1