PHP version requirements are not correct

[peter279k]

According to the composer.json file, this package requires php-5.4 version at least.

On require-dev setting, it requires phpunit/phpunit:^6.5 version. But this PHPUnit version requires php-7.0 version at least.

To fix above issue, I think it should let this package require php-7.2 or php-7.3 version because from php-5.4 to php-7.0 versions are too old/inactive.