Add missing stripe api key

stripe_checkout/stripe_checkout/management/commands/processevents.py

@@ -30,6 +30,7 @@ Amount: EUR {amount}
 
 class Command(BaseCommand):
     def handle(self, *args, **options):
+        stripe.api_key = settings.STRIPE_API_KEY
         unhandled_events = Event.objects.filter(handled=False).all()
         for event in unhandled_events:
             with transaction.atomic():