sign method

Implementation

@override
Future<String?> sign(String keyname, String message) async{
  try{
    print("OK");
    final signature = await methodChannel.invokeMethod<String>('sign', {'keyname': keyname, 'message':message});
    return signature ?? 'Could not sign message';
  } on PlatformException catch (ex){
    return ex.message ?? 'Unexpected error';
  }
}