8.0.0

• ⚠️ removed support for Python 3.6
• ⚠️ removed support for Python 3.7
• 🐛 MSS: fixed PEP 484 prohibits implicit Optional
• 💯 MSS: the whole source code was migrated to PEP 570 (Python positional-only parameters)
• 🆕 Linux: added mouse support (related to #55)
• 🐛 Linux: reset the X server error handler on exit to prevent issues with Tk/Tkinter (fixes #220)
• 🐛 Linux: refactored how internal handles are stored to fix issues with multiple X servers (fixes #210)
• 🐛 Linux: removed side effects when leaving the context manager, resources are all freed (fixes #210)
• 🆕 CLI: added --with-cursor argument
• tests: added PyPy 3.9, removed tox, and improved GNU/Linux coverage