Fix: Update actions/checkout version to v6 in workflow files

.github/workflows/test.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # Let's test the token first.
       - name: Check Authentication