remove cache... it's now a paid feature

Author: laksith19

.github/workflows/build.yaml

@@ -35,7 +35,6 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: DeterminateSystems/nix-installer-action@v14
-      - uses: DeterminateSystems/magic-nix-cache-action@v8
 
       - name: Build NixOS hosts
         run: nix develop -c colmena build --on ${{ matrix.host }}