CI - drop hhvm support (php is unsupported in HHVM 4)
CI - drop hhvm support (php is unsupported in HHVM 4)

https://hhvm.com/blog/2019/02/11/hhvm-4.0.0.html
https://travis-ci.org/EdgedesignCZ/phpqa/jobs/511546994#L521
EdgedesignCZ/phpqa,EdgedesignCZ/phpqa