This was possible since long (2013) but Google decided to keep it "banned" via policy which stated:
> An app downloaded from Google Play may not modify, replace or update its own APK binary code using any method other than Google Play's update mechanism.
https://arstechnica.com/information-technology/2013/04/googl...
https://gizmodo.com/5995416/google-bans-non-play-store-andro...