0.42.1

This release fixes a number of minor bugs and improves the documentation.

What's Changed

• Improved codestyle and added checks by @david-zwicker in #622
• Added argument post_step_hook to PDE class by @david-zwicker in #623
• Split examples into different categories by @david-zwicker in #625
• Removed pyupgrade since it is contained in ruff by @david-zwicker in #626
• Fix GridBase by @david-zwicker in #628
• Refactored logging by @david-zwicker in #630
• Added config option to affect how operators are implemented by @david-zwicker in #632
• Prevent usage of adaptive steppers with stochastic PDEs by @david-zwicker in #633

Full Changelog: 0.42.0...test