title: Angular "Ngx-Captcha" gives an error when run "ng build myAppName --prod" but without --prod is ok
body: <p>I use Ngx-Captcha(version 9.0.1) component in my Angular 7 project but when i build my project with <strong>--prod</strong> it gives this error:
  <strong>ERROR in : Directive BaseReCaptchaComponent in ./node_modules/ngx-captcha/ngx-captcha.d.ts has no selector, please add it!</strong></p>