Version 4

[bonny]

Version 4 is a major version because many incompatible API changes. For a regular user there is hopefully no noticeable change.

Since this is a major version let's try to fix as many major breaking changes in one go, so we hopefully don't have to bump to another major version again soon.

• [x] #293
• [x] #305
• [x] Make sure main index file does not crash on PHP versions < 7.4 so we don't risk upset existing users too much.
• [x] Add abstract class that loggers inherit (instead of SimpleLogger)
• [x] Move things from __construct to loaded() in both loggers and dropins, and remove __construct because
• [x] Change functions and methods to WordPress standard format
• [ ] #296
• [ ] Remove "Simple"-prefix from classes because redundant
• [ ] Rename classes and files from SimpleLogger » Simple_Logger
• [ ] Fix PHPStan level 0 errors
• [ ] Should a un-namespaced SimpleLogger-class be included to make an upgrade less risky? It could trigger a call to _deprecated_function() or similar on __construct()

After release

• Write blog post
• Update docs (regenerate JSON-files and deploy)