Fix Windows build: add missing PyQt6.sip hidden import

.gitea/workflows/build-windows.yaml

@@ -23,7 +23,7 @@ jobs:
 
       - name: Build Executable
         run: |
-          wine pyinstaller --onefile --windowed --hidden-import=pkgutil --name TeletextEditor_Windows.exe --paths src --add-data "app_icon.png;." --icon=app_icon.ico src/main.py
+          wine pyinstaller --onefile --windowed --hidden-import=pkgutil --hidden-import=PyQt6.sip --name TeletextEditor_Windows.exe --paths src --add-data "app_icon.png;." --icon=app_icon.ico src/main.py
 
       - name: Upload Artifact
         uses: actions/upload-artifact@v3