PySide6<=6.4.3 needed for internal installs

[EthanS94]

For our internal pycinema installs, I need to hold PySide6 to 6.4.3. If I don't, cinema builds fine, but I get the following error when running it:

qt.qpa.plugin: From 6.5.0, xcb-cursor0 or libxcb-cursor0 is needed to load the Qt xcb platform plugin.
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vkkhrdisplay, vnc, wayland-egl, wayland, xcb.

Abort (core dumped)

Other than trying an older version then 6.5, I haven't looked more into this. Setting "PySide6<=6.4.3", in setup.py is the workaround I'm using.

[dhrogers]

As long as the tests and examples run with 6.4.3, this should be fine.