Add release with new binary

.github/workflows/ci.yml

@@ -3,6 +3,7 @@ on:
   pull_request:
   push:
     branches: ["main"]
+    tags: ["v*"]
 jobs:
   build:
     name: Build packages
@@ -20,3 +21,13 @@ jobs:
     - run: nix --print-build-logs build .#packages.$SYSTEM.default
       env:
         SYSTEM: ${{ matrix.system }}
+
+    - name: Prepare release artifact
+      if: startsWith(github.ref, 'refs/tags/')
+      run: cp result/bin/mkv mkv-${{ matrix.system }}
+
+    - name: Create release
+      if: startsWith(github.ref, 'refs/tags/')
+      uses: softprops/action-gh-release@v2
+      with:
+        files: mkv-${{ matrix.system }}