I'm currently looking into bringing this app into the FOSS appstore called F-Droid.

Currently I see two things that would make packaging more easy if they would get changed:

1. versions are not tagged, so it's not really clear based on what commit each version is build. For example I see you bumped version in 2b879bb, but was 3.4.1 build based on this commit?
2. it would be cool if you could provide metadata about the app based on fastlane structure. This would make it way easier from the F-Droid side because you control the metadata and changing the metadata will not require work on the F-Droid side.