Added PySide6 support

Task-Id: KDDW-27

python/examples/main.py

@@ -9,11 +9,11 @@
 # Contact KDAB at <info@kdab.com> for commercial licensing options.
 #
 
-
-from PySide2 import QtWidgets, QtCore 
 from PyKDDockWidgets import KDDockWidgets
 from MyMainWindow import MyMainWindow
 
+from PySide import QtWidgets, QtCore
+
 import sys
 import rc_assets