Make the appstream file validate with version >= 0.6

Fixes: #97

Author: bigon

system-config-printer.appdata.xml.in

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<application>
-  <id type="desktop">system-config-printer.desktop</id>
+<component type="desktop">
+  <id>system-config-printer.desktop</id>
   <metadata_license>CC0</metadata_license>
   <project_license>GPL-2.0+</project_license>
   <_name>Print Settings</_name>
@@ -29,5 +29,5 @@
     <dbus type="system">org.fedoraproject.Config.Printing</dbus>
   </provides>
 
-  <updatecontact>zdohnal@redhat.com</updatecontact>
-</application>
+  <update_contact>zdohnal@redhat.com</update_contact>
+</component>