Metadata: make F-Droid icon happy

Summary:
I'm just blindly trusting this comment from Licaon_Kter lol:

https://gitlab.com/fdroid/fdroiddata/-/commit/67bfb5d0a87f6ee12137a39c095bda44187592b9#note_2139527294

The image was just copied from the latest high-quality logo available:

https://gitpull.it/source/libre-busto/browse/master/app/src/main/res/drawable-xxxhdpi/ic_launcher.png;8edbdcb07bba722d7f7639ff7cd9bbea90141ce0

Test Plan: Look at the image. That is beautiful. Just like you.

Reviewers: fabio.mazza

Reviewed By: fabio.mazza

Subscribers: Libre BusTO

Tags: Libre BusTO

Differential Revision: https://gitpull.it/D169