Fix cloning of submodules

Author: liufengyun

.github/workflows/ci.yaml

@@ -93,6 +93,8 @@ jobs:
 
       - name: Test
         run: |
+          git submodule sync
+          git submodule update --init --recursive --jobs 7
           ./project/scripts/sbt ";dotty-bootstrapped/compile ;dotty-bootstrapped/test;sjsSandbox/run;sjsSandbox/test;sjsJUnitTests/test ;configureIDE"
           ./project/scripts/bootstrapCmdTests