PHP 8.5: replace guzzle with native URI-parser

This library now depends on guzzle/psr7 just for it's URI-parsing capabilities.
PHP 8.5 has brought us native URI-parsing, so as soon as the minimum required PHP-version for this library becomes PHP 8.5, we should remove guzzle in favour of the native parser:

https://www.php.net/releases/8.5/en.php#new-uri-extension