ci: bump actions/checkout from 4 to 6 (#36)

Author: andywithcamera

.github/workflows/static.yml

@@ -30,7 +30,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
       - name: Setup Pages
         uses: actions/configure-pages@v6
       - name: Upload artifact