fix caching in ci

.github/workflows/build.yml

@@ -32,19 +32,17 @@ jobs:
       - uses: actions/checkout@v4
       
       - name: "Install Nix ❄️"
-        uses: cachix/install-nix-action@v26
+        uses: cachix/install-nix-action@v27
         with:
           nix_path: nixpkgs=channel:nixos-unstable
 
       - name: "Install Cachix ❄️"
-        uses: cachix/cachix-action@v14
+        uses: cachix/cachix-action@v15
         with:
           name: zackartz
           authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
-         
-        
+          signingKey: "${{ secrets.CACHIX_SIGNING_KEY }}"
+
       - name: "Build NixOS config ❄️"
-        env:
-          CACHIX_SIGNING_KEY: "${{ secrets.CACHIX_SIGNING_KEY }}"
         run: |
           nix build .\#nixosConfigurations."earth".config.system.build.toplevel