title: Stripe iOS, build configuration warning
body: <p>When I build my iOS app that uses Stripe and run it I get this message:</p>
  
  <blockquote>
    <p>⚠️ Warning! You're building your app in a non-debug configuration, but appear to be using your Stripe test key. Make sure not to submit to the App Store with your test keys!⚠️</p>
  </blockquote>
  
  <p>I am using the DEBUG scheme which uses the xCode DEBUG configuration to my understanding.</p>
  
  <p>What am I missing to get this right and avoid getting this warning?</p>