build.py: Remove --app-target option

It was no longer used since d04355dfb0

Change-Id: I048d8566babec1e926cbf32916c4d88d474d8ef8
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

scripts/build.py

@@ -73,9 +73,6 @@ def get_arguments():
     parser.add_argument('--python-path',
                         help='Path to python libraries for use by cdbextension (Windows)')
 
-    parser.add_argument('--app-target', help='File name of the executable / app bundle',
-                        default=('Qt Creator.app' if common.is_mac_platform()
-                                 else 'qtcreator'))
     parser.add_argument('--python3', help='File path to python3 executable for generating translations',
                         default=default_python3())