mbedtls now has submodules

Update github workflow to add "--recursive" to
"git submodule update --init"

Author: peterharperuk

.github/workflows/cmake.yml

@@ -26,7 +26,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Checkout submodules
-      run: git submodule update --init
+      run: git submodule update --init --recursive
 
     - name: Create Build Environment
       # Some projects don't allow in-source building, so create a separate build directory