Checkout submodules in different step

.forgejo/workflows/build.yml

@@ -17,8 +17,8 @@ jobs:
         apt-get install -y devscripts debhelper equivs git nodejs sudo
     - name: Checkout Sources
       uses: actions/checkout@v4
-      with:
-          submodules: recursive
+    - name: Checkout submodules
+      run: git submodule update --init --depth 16 --jobs 3
     - name: Setup build depends
       run: sudo mk-build-deps -i
     - name: Build Kernel