Default xdebug version

[GrahamCampbell]

I think xdebug 3 should be the default on PHP 7.3 or higher (but not 7.2, because it doesn't work with the latest version of phpunit which still supports PHP 7.2).

[shivammathur]

@GrahamCampbell After 2.9.0, it should setup Xdebug 2.9.8 on PHP 7.2.
Please test and let me know

[GrahamCampbell]

PHPUnit 8.5 has now been patched to work with Xdebug 3.0. I don't know if we want to change the default back to 3.0.0, or leave it on 2.9.8, since PHPUnit 7.5 still won't work properly.

[shivammathur]

Will test this before next release and if it is working on PHP 7.2, I will remove the workaround I added to setup Xdebug 2.

The php7.2-xdebug version on the ubuntu runner will anyway change to Xdebug 3 once it is updated on the PPA. Then the workaround will add 30-40 sec to the runtime for everyone on PHP 7.2, if not removed. Instead I will add a coverage: xdebug2 option for PHPUnit 7 users.

[GrahamCampbell]

Cool. :)