Test cachix

Signed-off-by: Henri Rosten <henri.rosten@unikie.com>

.github/workflows/nix-build.yml

@@ -0,0 +1,25 @@
+name: nix build
+
+on:
+  pull_request:
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  checks:
+    name: Run nix build for the selected outputs before merging
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: cachix/install-nix-action@v22
+        with:
+          nix_path: nixpkgs=channel:nixpkgs-unstable
+          extra_nix_config: |
+            trusted-public-keys = cache.vedenemo.dev:RGHheQnb6rXGK5v9gexJZ8iWTPX6OcSeS56YeXYzOcg= cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
+            substituters = https://cache.vedenemo.dev https://cache.nixos.org/
+      - uses: cachix/cachix-action@v12
+        with:
+          name: cachix-cache
+          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+      - run: nix build .#packages.x86_64-linux.generic-x86_64-debug