Finalized 1.0

Hier ist der Entwurf für die GitHub-Changelog-Nachricht auf Englisch, wie gewünscht:

Release Notes

This release modernizes the codebase by increasing the minimum PHP requirement to 8.0 and introducing support for PSR-18 HTTP clients.

Breaking Changes

• Requires PHP 8.0 or higher.
• Strict type hints and return types have been added to all classes and interfaces.

New Features

• Added a transport client implementation for PSR-18 compatible HTTP clients and PSR-17 factories. This offers an alternative to the built-in cURL transport.
• Updated composer suggestions to include PSR-18 and PSR-17 packages.

Improvements

• Refactored internal logic to use PHP 8 features, including match expressions for log level mapping.
• Error handling now catches Throwable to better handle runtime errors during delivery.
• Updated README with comprehensive usage examples for both cURL and PSR-18 transports.

Maintenance

• Added a full test suite for logger and transport logic.
• Added static analysis configuration (PHPStan) and refactoring tools (Rector) to the development workflow.