ci: Use latest versions of github actions

Author: rvl

.github/workflows/build.yml

@@ -9,15 +9,12 @@ jobs:
     runs-on: ubuntu-latest
     name: Nix Flake - Linux
     steps:
+      - name: Clone project
+        uses: actions/checkout@v5
       - name: Install Nix
-        uses: cachix/install-nix-action@v13
+        uses: cachix/install-nix-action@v31
         with:
-          install_url: https://nixos-nix-install-tests.cachix.org/serve/i6laym9jw3wg9mw6ncyrk6gjx4l34vvx/install
-          install_options: '--tarball-url-prefix https://nixos-nix-install-tests.cachix.org/serve'
-          extra_nix_config: |
-            experimental-features = nix-command flakes
-            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
-      - name: Clone project
-        uses: actions/checkout@v2
+          github_access_token: ${{ secrets.GITHUB_TOKEN }}
       - name: Build
         run: nix build
+      - run: nix flake check