Release version 0.5.4
Release version 0.5.4

hughsie/appstream-glib,ikeydoherty/appstream-glib,ximion/appstream-glib,ximion/appstream-glib,hughsie/appstream-glib,hughsie/appstream-glib,ximion/appstream-glib,ikeydoherty/appstream-glib