Checkout submodules for auto-publishing (#236)

Author: mosuem

.github/workflows/publish.yaml

@@ -171,6 +171,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
+        with:
+          submodules: ${{ inputs.checkout_submodules }}
 
       - uses: subosito/flutter-action@2783a3f08e1baf891508463f8c6653c258246225
         if: ${{ inputs.use-flutter }}