Update dependencies and minor updates

• Enabling more up-to-date Guzzle components
• Enabling PHPUnit 10
• Minor code review

Add support for user lists, list and wantlist endpoints

• getUserLists
• getLists
• getWantlist

Dependency fix for PHP 8.x support

Full Changelog: v2.0.1...v2.0.2

Prepare for use in calliostro/discogs-bundle

• Lower minimum versions of the required packages
• DiscogsClient extends GuzzleClient to provide PHPDOC for API methods
• Added reference to calliostro/discogs-bundle for Symfony 5

First release of this fork

• support for PHP 7.3, 7.4 and 8.0
• more Discogs API methods available
• more improvements

Thanks to ricbra/php-discogs-api and AnssiAhola/php-discogs-api, which this is based on.