Allow PHPUnit 8

[Engerim]

• run tests with phpunit 8.0
• allow failures for dev-master runs
• fix Compatibility with phpunit 8? #52

[johnkary]

Hi @Engerim, Thank you for adding this support to the build matrix! Looks like things are working well against PHPUnit 8.

Could you please see my comment about having removed nightly from the build matrix?

[Engerim]

Hi @johnkary I don't see any comment about the nightly build, but I can add the nightly php again

[johnkary]

@Engerim Yes, could we please add - nightly back to PHP build matrix?

[Engerim]

Nightly is added again, but with allowed failures. php nightly is for now php 8.0.0-dev instead of 7.4.0-dev so i allow them to fail for now.
See also this tweet and comments https://twitter.com/kelunik/status/1094228271942848518?s=21

Also interesting https://travis-ci.community/t/add-php-7-4-branch-to-test-against/2179

[mazsudo]

any plan to merge/release this @johnkary ? love this library and would be glad to keep using it with phpunit8 ;)
could also help to preprare a next version as TestListener interface seems deprecated now with phpunit8 if you want ;)

[Engerim]

ping @johnkary everything works

[johnkary]

@Engerim Thank you for your help to allow PHPUnit 8 compatibility!