Hello,
I created a fork a GB Studio 2 that export natively game in pocket file.
https://github.com/BestPig/gb-studio#analogue-pocket-export
So it should be easy to port your game without the pain of migrating to GB Studio 3.0 :)
I don't know if migrating a game from 1.0 to 2.0 breaks stuff, so maybe only works for game made with the 2.0.
If you have any issue with it, don't hesitate to contact me.