Bump MODULE_VERSION to 5.3.1

Change-Id: I49f696c528ec631cdc5aac2dc3f0402646a14de0
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>

.qmake.conf

 load(qt_build_config)
 CONFIG += qt_example_installs
 
-MODULE_VERSION = 5.3.0
+MODULE_VERSION = 5.3.1