[FEAT] Use go-appimage appimagetool for fuse3 compatibility.

[Samueru-sama]

This appimage uses the old version of appimagetool that depends on fuse2, which is starting to not be shipped by default in distros.

There is this newer implementation by probonopd that makes them work with fusermount3: https://github.com/probonopd/go-appimage

Using this appimagetool is the about the same as the old tool, just that you have to define VERSION=, which for example can be like this:

ARCH=x86_64 VERSION=$(./appimagetool -v | grep -o '[[:digit:]]*') ./appimagetool -s ./Brave.AppDir