Maintenance
- Remove support for PHP 7.0 since it is no longer supported and adopt PHP 7.1 (#4)
- Remove support for PHP 7.1 since it is no longer supported (#5)
- Support for PHP 7.3 (#6)
- Consistence 2.x (#7)
BC breaks
Since new language features from PHP 7.1 are used some method signatures have changed. This means that if you were extending/implementing them, you need to update the method signatures to match the new form.