Dear PyGUI version upgrade changes GUI creation methods.

[MaybeNotABob]

Extract copied from Dear PyGUI:
https://dearpygui.readthedocs.io/en/latest/tutorials/first-steps.html

The main script must always:

Create the context create_context
Create the viewport create_viewport
Setup dearpygui setup_dearpygui
Show the viewport show_viewport
Start dearpygui start_dearpygui
Clean up the context destroy_context

This therefore changes the steps in previous versions (and this repo) such as set_main_window_size(540, 720) which no longer exists.