ci: run on nix-flakes

.forgejo/workflows/test.yml

@@ -8,11 +8,7 @@ on:
 
 jobs:
   test-cache:
-    strategy:
-      matrix:
-        os: [ubuntu-latest]
-
-    runs-on: ${{ matrix.os }}
+    runs-on: nix-flakes
 
     steps:
       - name: Checkout repository
@@ -27,18 +23,6 @@ jobs:
           apt-get install -qy sudo &&
           curl -sSL https://get.docker.com/ | sh
 
-      - uses: pnpm/action-setup@v3
-      - uses: actions/setup-node@v4
-        with:
-          cache: pnpm
-          cache-dependency-path: pnpm-lock.yaml
-
-      - name: Build
-        run: pnpm install && pnpm build
-
-      - name: Install Nix
-        uses: https://github.com/DeterminateSystems/nix-installer-action@v9
-
       - name: Setup Attic Cache
         uses: ./
         with: