chore: using another arm for arm64 configs

.github/workflows/test.yml

@@ -19,10 +19,11 @@ jobs:
       - name: Check up flake configuration
         run: nix flake check --all-systems --show-trace
 
-  build-instances:
+  build-x86_64:
     strategy:
+      fail-fast: false
       matrix:
-        instance: [ 1, 2, 3, 4 ]
+        instance: [ 1, 2, 3 ]
 
     runs-on: ubuntu-latest
 
@@ -38,3 +39,24 @@ jobs:
 
       - name: Build NixOS configuration
         run: nix build .#nixosConfigurations.Kolyma-${{ matrix.instance }}.config.system.build.toplevel --show-trace
+
+  build-arm64:
+    strategy:
+      fail-fast: false
+      matrix:
+        instance: [ 4 ]
+
+    runs-on: ubuntu-latest-arm
+
+    steps:
+      - name: Check out the repository
+        uses: actions/checkout@v4
+
+      - name: Install Nix
+        uses: DeterminateSystems/nix-installer-action@main
+
+      - name: Cache Nix store
+        uses: DeterminateSystems/magic-nix-cache-action@main
+
+      - name: Build NixOS configuration
+        run: nix build .#nixosConfigurations.Kolyma-${{ matrix.instance }}.config.system.build.toplevel --show-trace