workflows: Add deploy stage to CI pipeline

.github/workflows/ci.yml

@@ -0,0 +1,23 @@
+name: "CI"
+on:
+  push:
+    branches: [main]
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+      - uses: cachix/install-nix-action@v31
+      - uses: cachix/cachix-action@v15
+        with:
+          name: sebastian-stork
+          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
+      - run: nix flake --extra-experimental-features pipe-operators check
+  deploy:
+    needs: check
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/checkout@v5
+      - run: git push origin HEAD:deploy --force