chore(deps): update actions/checkout action to v5 (#13)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/ci.yml

@@ -59,7 +59,7 @@ jobs:
       matrix:
         host: [higgins, benson, spaceblack, dunston]
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: DeterminateSystems/nix-installer-action@v19
       - uses: DeterminateSystems/magic-nix-cache-action@v13
       - name: Build toplevel for ${{ matrix.host }}