checkout submodules in workflow

Author: MalteSchwitters

.github/workflows/docker.yml

@@ -34,6 +34,9 @@ jobs:
     steps:
       - name: Checkout repository
         uses: actions/checkout@v3
+        with:
+          submodules: 'true'
+          token: ${{ secrets.PERSONAL_ACCESS_TOKEN }}
 
       # Install the cosign tool except on PR
       # https://github.com/sigstore/cosign-installer