update pip source for opcua-client

[lm906]

Today I wanted to test my own implementation of OPC UA with the Freeopcuaclient. I noticed that after specifying the certificates under "Settings>Client application certificate" opcua-client crashes with the message:

File "/home/.pyenv/versions/3.12.1/envs/thesis/lib/python3.12/site-packages/uaclient/mainwindow.py", line 311, in show_application_certificate_dialog
if ret == QDialog.Accepted:
^^^^^^^
NameError: name 'QDialog' is not defined
Abgebrochen (Speicherabzug geschrieben)

I am using PyQt5 (5.15.10) and Python (3.12.1) in a pyenv.
If I use the sources from the project (start the program with python app.py) it works. Probably the pip package would have to be adapted to the new sources.