How to alter icons in dist folder for cryptomator-develop?

I’m interested in helping with Issue #2517 on Github (bringing the app icon in line with Apple’s style guide for the Mac version of Cryptomator), but after looking through and playing with the source code and icons in the cryptomator-develop branch (after downloading from Github), I’m not sure how to alter Cryptomator.icns in dist/mac/resources.

I’ve tried changing all the icons in src/main/resources/img and then building from source (via mvn install clean), but Cryptomator.icns remains unchanged. Does anyone know what I can do? Thank you so much in advance!