message: [now-cli] Don't print "Error starting dev server" message by default
  It's not useful information and distracts from whatever the actual error
  message was from the dev server, which is what the user is actually
  interested in.
diff: @@ -1478,7 +1478,7 @@ export default class DevServer {
  // `starDevServer()` threw an error. Most likely this means the dev
  // server process exited before sending the port information message
  // (missing dependency at runtime, for example).
  - console.error(`Error starting "${builderPkg.name}" dev server:`, err);
  + debug(`Error starting "${builderPkg.name}" dev server: ${err}`);
  await this.sendError(
  req,
  res,
  