4.0.3

⚠️ The source code is now derived from master, where Python 2 support has been dropped.

• new contributors: @grintor, @SergeyKalutsky
• Windows: use our own instances of GDI32 and User32 DLLs (backported from 5.0.0)
• Windows: fix the screen bounding AiO rectangle (backported from 5.0.0)