Fix pipeline with fake envs

Dockerfile

@@ -29,6 +29,7 @@ ENV DJANGO_SETTINGS_MODULE "majak.settings.production"
 # fake values for required env variables used to run collectstatic during build
 RUN DJANGO_SECRET_KEY=x DATABASE_URL=postgres://x/x DJANGO_ALLOWED_HOSTS=x \
     OIDC_RP_CLIENT_ID=x OIDC_RP_CLIENT_SECRET=x OIDC_RP_REALM_URL=x \
+    CELERY_BROKER_URL=x CELERY_RESULT_BACKEND=x \
     python manage.py collectstatic
 
 EXPOSE 8000