Move Nix builds to separate file

Signed-off-by: Wiktor Kwapisiewicz <[email protected]>

.github/workflows/ci.yml

@@ -23,21 +23,6 @@ jobs:
         run: |
           docker buildx build --platform linux/amd64 --file ci/e2e.dockerfile .
 
-  nix-build:
-     name: Run nix-build
-     runs-on: ${{ matrix.os }}
-     continue-on-error: true
-     strategy:
-      matrix:
-        include:
-          - os: ubuntu-latest
-          - os: macos-latest
-     steps:
-       - uses: actions/checkout@v3
-       - uses: nixbuild/nix-quick-install-action@v26
-       - run: nix flake check
-       - run: nix build .#pysequoia
-
   build:
     name: Build and check
     strategy:

.github/workflows/nix.yml

@@ -0,0 +1,23 @@
+name: Nix
+
+on: [push, pull_request]
+
+concurrency:
+  group: ${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  check-and-build:
+     name: Run nix flake check and nix build
+     runs-on: ${{ matrix.os }}
+     continue-on-error: true
+     strategy:
+      matrix:
+        include:
+          - os: ubuntu-latest
+          - os: macos-latest
+     steps:
+       - uses: actions/checkout@v3
+       - uses: nixbuild/nix-quick-install-action@v26
+       - run: nix flake check
+       - run: nix build .#pysequoia