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

Author: renovate[bot]

.github/workflows/nix-github-actions.yml

@@ -10,7 +10,7 @@ jobs:
     outputs:
       matrix: ${{ steps.set-matrix.outputs.matrix }}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: cachix/install-nix-action@v30
       - id: set-matrix
         name: Generate Nix Matrix
@@ -26,6 +26,6 @@ jobs:
     strategy:
       matrix: ${{fromJSON(needs.nix-matrix.outputs.matrix)}}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: cachix/install-nix-action@v30
       - run: nix build -L '.#${{ matrix.attr }}'