message: fix(builders): error when process is closed with non zero error code
diff: @@ -32,11 +32,6 @@ export function spawnAsObservable(
  ): Observable<{ stdout?: string, stderr?: string }> {
  return new Observable(obs => {
  const proc = spawn(command, args, options);
  - if (!proc) {
  - obs.error(new Error(`${command} cannot be spawned.`));
  - return;
  - }
  -
  if (proc.stdout) {
  proc.stdout.on('data', data => obs.next({ stdout: data.toString() }));
  }
  @@ -47,7 +42,13 @@ export function spawnAsObservable(
  proc
  .on('error', err => obs.error(err))
  - .on('close', () => obs.complete());
  + .on('close', code => {
  + if (code !== 0) {
  + obs.error(new Error(`${command} exited with ${code} code.`));
  + }
  +
  + obs.complete();
  + });
  return () => {
  if (!proc.killed) {
  