(Go version) Multi platform build (#319)

.github/workflows/build.yml

@@ -20,8 +20,7 @@ jobs:
       with:
         go-version: ^1.15
     - name: Build binaries
-      working-directory: cmd/blackbox
-      run: go build
+      run: go run build/build.go
     - name: Run unit tests
       run: go test ./...
     - name: Run integration tests