`current_time` return type changed

https://github.com/szepeviktor/phpstan-wordpress/blob/5d1c8ce8a8e718465692d79a7912dfefed6d9193/tests/data/current_time.php#L27

Has core changed its type??
No: _int|string Integer if $type is 'timestamp' or 'U', string otherwise._

https://app.travis-ci.com/github/szepeviktor/phpstan-wordpress/jobs/604190969#L481 👀 

Anyone with a keyboard? :)