Set prgname to application ID (#249)

Using the application ID ensures that Wayland compositors could match the
window with the application and show the appropriate icon for them.

Author: City-busz

src/warpinator.py

@@ -1424,6 +1424,8 @@ def do_startup(self):
         Gtk.Application.do_startup(self)
         logging.info("Initializing Warpinator")
 
+        GLib.set_prgname("org.x.Warpinator")
+
         prefs.prefs_settings.connect("changed::" + prefs.TRAY_ICON_KEY, self.on_prefs_changed)
 
         vt = GLib.VariantType.new("s")