Compress all resources

data/rugby.gresource.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <!--
-  SPDX-FileCopyrightText: 2012-2020 Bruce Cowan <bruce@bcowan.me.uk>
+  SPDX-FileCopyrightText: 2012-2021 Bruce Cowan <bruce@bcowan.me.uk>
 
   SPDX-License-Identifier: GPL-3.0-or-later
 -->
 <gresources>
   <gresource prefix="/uk/me/bcowan/rugby">
-    <file preprocess="xml-stripblanks">interface.ui</file>
-    <file preprocess="xml-stripblanks">prefs.ui</file>
+    <file preprocess="xml-stripblanks" compressed="true">interface.ui</file>
+    <file preprocess="xml-stripblanks" compressed="true">prefs.ui</file>
     <file compressed="true">rugby.css</file>
   </gresource>
 </gresources>