v0.4.1

What's Changed

• Replace azjezz/psl with php-standard-library/php-standard-library by @jcmvrij in #52
• Add Describable interface for human-readable source descriptions by @robertvansteen in #53

New Contributors

• @jcmvrij made their first contribution in #52

Full Changelog: v0.4.0...v0.4.1