Flutterでfirebase CERTIFICATE_VERIFY_FAILED: unable to get local issuer certificateが出たとき

main.dartに以下のクラスを追加

class MyHttpOverrides extends HttpOverrides {
  @override
  HttpClient createHttpClient(SecurityContext context) {
    return super.createHttpClient(context)
      ..badCertificateCallback =
          (X509Certificate cert, String host, int port) => true;
  }
}

main()を変更

void main() {
  HttpOverrides.global = new MyHttpOverrides();
  runApp(MyApp());
}