Update actions/checkout action to v5

Author: renovate[bot]

.github/workflows/ci.yml

@@ -22,7 +22,7 @@ jobs:
           #- ubuntu-22.04-arm
           #- macos-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: cachix/install-nix-action@v31
       - uses: cachix/cachix-action@v16
         with: