Add simple CI to build binaries

.github/workflows/macos.yml

@@ -0,0 +1,33 @@
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        arch:
+          - amd64
+          - arm64
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-go@v2
+        with:
+          go-version: "1.20"
+      - run: |
+          go build -o bin/buildctl-${{ matrix.arch }} ./cmd/buildctl
+          go build -o bin/buildkitd-${{ matrix.arch }} ./cmd/buildkitd
+        env:
+          GOOS: darwin
+          GOARCH: ${{ matrix.arch }}
+      - uses: actions/upload-artifact@v3
+        with:
+          name: ${{ matrix.arch }}
+          path: bin/*
+      - uses: softprops/action-gh-release@v1
+        if: startsWith(github.ref, 'refs/tags/')
+        with:
+          files: bin/*
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}