v5.0.0

Changed

• Bumped minimum required PHP version to 8.1 and ensured support up to PHP v8.4
• PHLAK\Twine\Str now exposes $string and $encoding as public readonly properties
• Refacotored PHLAK\Twine\Config\* classes to enums (usage remains unchanged)
• Updated PHLAK\Twine\Str object serialization to use magic methods
  • PHLAK\Twine\Str no longer implements Serializable
  • serialize() and unserialize() methods replaced with __serialize() and __unserialize() respectively