Add cachix workflow

Author: lukasl-dev

.github/workflows/cachix.yml

@@ -0,0 +1,21 @@
+name: Cachix
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+
+jobs:
+  cache:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - uses: cachix/install-nix-action@v25
+      with:
+        nix_path: nixpkgs=channel:nixos-unstable
+    - uses: cachix/cachix-action@v14
+      with:
+        name: rime
+        authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+    - run: nix build .#rime