Update actions/checkout action to v6

Author: renovate[bot]

.github/workflows/deploy.yaml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-    - uses: actions/checkout@v4.2.2
+    - uses: actions/checkout@v6.0.1
     - uses: cachix/install-nix-action@v30
       with:
         install_url: https://nixos-nix-install-tests.cachix.org/serve/i6laym9jw3wg9mw6ncyrk6gjx4l34vvx/install