switch from PyQt6 to PySide6

PySide6 uses LGPL instead of GPL, which is much nicer to work with.

raven/plugins/ravenlogplugin.py

@@ -1,8 +1,8 @@
 import sys
 from typing import Optional
 
-from PyQt6.QtCore import Qt
-from PyQt6.QtWidgets import QDockWidget, QLabel
+from PySide6.QtCore import Qt
+from PySide6.QtWidgets import QDockWidget
 
 import constants
 from aboutdialog import AboutDialog