Our upgrade process work on the host OS level (the ./launcher rebuild app) and when we have to update something like Ruby, Nginx, PostgreSQL, Redis, ImageMagick or any of the many dependencies we give you a brand new image.
Also upgrading PostgreSQL would be more complicated in this, unless you use the container for web only, and point PostgreSQL and Redis to the compatible Azure managed services.
But I wouldn’t recommend this for someone who just want a small community up. For that our guide to setup on a $10 Digital Ocean or $5 Vultr server is very good and low maintenance. If your site is bigger than that, you should be able to afford Communiteq (formerly DiscourseHosting) or our own hosting. You can even use the Patreon plugin to help fund a big community hosting fees.