README.me - please add instructions to "compile" a simple app

[zackees]

Please add to your readme how someone uses this framework to bundle the simplest app possible. The majority of people coming to this github project are looking for this.

[nickchomey]

More appropriately, perhaps the readme should be updated to reflect what seems to have been a perfectly reasonable decision to stop maintaining PyOxidizer

https://gregoryszorc.com/blog/2024/03/17/my-shifting-open-source-priorities/