github: checkout the right commit of kuroko

.github/workflows/build.yml

@@ -13,6 +13,8 @@ jobs:
         with:
           repository: kuroko-lang/kuroko
           path: kuroko
+      - name: Checkout Kuroko
+        run: git submodule update --init kuroko
       - name: Pull Builder Image
         run: docker pull toaruos/build-tools:1.99.x
       - name: Run Builder