Add cone-mode fix to sparse-checkout

Author: thomas-bc

.github/workflows/ext-raspberry-led-blinker.yml

@@ -74,6 +74,7 @@ jobs:
         uses: actions/checkout@v4
         with:
           sparse-checkout: 'requirements.txt'
+          sparse-checkout-cone-mode: false
       - name: "Setup environment"
         run: |
           python -m venv venv