ci: upgrade GitHub Actions for Node 24 (#3)

Author: Pigbibi

.github/workflows/ci.yml

@@ -9,7 +9,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
           python-version: "3.12"