Now that we have added plugs to allow accessing the display, the snap needs
a desktop file. And bonus point, it will appear on the menu when it's
installed, and once you make a stable relase, it will appear in the gnome
software center app! So, one-click install for parity :)
Closes: #7056
For commits with an annotated tag, that tag will be the version. For other commits, a git identifier will be used.
This way, there is no need to manually edit the snap version.
