Use Magic Nix Cache (#6)

Author: vic

.github/workflows/test.yml

@@ -6,10 +6,10 @@ jobs:
   tests:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2.4.0
-    - uses: cachix/install-nix-action@v15
-      with:
-        extra_nix_config: |
-          access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
-    - run: nix build
-    - run: nix flake check
+    - uses: actions/checkout@v3
+    - name: Install Nix
+      uses: DeterminateSystems/nix-installer-action@v4
+    - name: Magic Nix Cache
+      uses: DeterminateSystems/magic-nix-cache-action@v1
+    - name: Test flake output
+      run: nix flake check