Upgrade Houdini install script to PySide6

Author: LucaScheller

tools/update_manager.py

@@ -10,7 +10,11 @@
 import zipfile
 from urllib import request
 
-from PySide2 import QtCore, QtGui, QtWidgets
+try:
+    from PySide6 import QtCore, QtGui, QtWidgets
+except ImportError:
+    from PySide2 import QtCore, QtGui, QtWidgets
+
 
 # To run, execute this in the Houdini/Maya
 """