chore: use checkout v6

Author: Burnett01

.github/workflows/test.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v6
     - name: Insert to demo database (using env)
       uses: ./
       env: