message: Add required header for sign-in (lib)
diff: @@ -5828,6 +5828,7 @@ error Context::signUpWithProvider(
  req.host = urls::API();
  req.relative_url = ss.str();
  req.payload = Json::StyledWriter().write(user);
  + req.additionalHeaders["Referer"] = "daneel.debug";
  HTTPSResponse resp = toggl_client->Post(req);
  if (resp.err != noError) {
  