שדרוג נכשל עם: חסר שקע Nginx "לפני-שרת"... discourse_docker אינו תואם לגרסת Discourse שנבחרה

I’ve tracked down the issue — it was caused by the discourse-images-guardian plugin from @mbcahyono which needed the nginx.sample.conf file updating, I have done this and created a pull request to fix it.