enable cachix

.github/workflows/ci.yml

@@ -10,15 +10,17 @@ jobs:
     strategy:
       matrix:
         runner:
-          - macos-latest
-          - ubuntu-latest
+          - ubuntu-latest-4-cores
     runs-on: ${{ matrix.runner }}
     steps:
       - uses: actions/checkout@v4
       - uses: cachix/install-nix-action@v22
+      - uses: cachix/cachix-action@v14
+        with:
+          name: freckle-flakes
+          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
       - uses: DeterminateSystems/magic-nix-cache-action@v2
       - name: Check
-        # Build parallelism is reduced here to increase probability of build success.
-        # This decision is influenced by the opinion that the speed of CI is not very
-        # important for this repository.
-        run: nix flake check ./main --max-jobs 1
+        # run: nix flake check ./main
+        run: nix build ./main#aws-cli-default
+        run: nix build ./main#ghc-9-4-6