desktop file shipped with package is incomplete

[anarcat]

This is the desktop file shipped in the 0.8.2 release:

$ tar -x -O -f  Supersonic-0.8.2-linux-x64.tar.xz usr/loc
al/share/applications/Supersonic.desktop;  echo
[Desktop Entry]
Type=Application
Name=Supersonic
Exec=supersonic 
Icon=Supersonic
Keywords=fyne;

while it ... works, it's a far cry from the much more complete, manually built .desktop file available in the source tree:

https://github.com/dweymouth/supersonic/blob/main/res/supersonic-desktop.desktop

the build process should end up generating a file like that instead.

this particularly affects the flatpak package, which (used to) rely on the shipped desktop file (flathub/io.github.dweymouth.supersonic#47). in the beta, it switched to installing the other file manually (flathub/io.github.dweymouth.supersonic#50), but it would be nice to harmonize that across packages and distribution mechanisms.