ci: Use newer actions

.github/workflows/ci-nix.yml

@@ -7,12 +7,8 @@ jobs:
     name: Rust project
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2.3.4
-    - uses: cachix/install-nix-action@v16
-      with:
-        #install_url: https://nixos-nix-install-tests.cachix.org/serve/lb41az54kzk6j12p81br4bczary7m145/install
-        #install_options: '--tarball-url-prefix https://nixos-nix-install-tests.cachix.org/serve'
-        extra_nix_config: |
-          experimental-features = nix-command flakes
+    - uses: actions/checkout@v3
+    - name: Install Nix
+      uses: DeterminateSystems/nix-installer-action@main
     - run: nix develop -c rustc --version
-    - run: $(nix-build --no-out-link)/bin/rust-nix-template
+    - run: nix run