[CI] PHP CS Fixer it up

[bocharsky-bw]

No description provided.

[bocharsky-bw]

hm, tests started failing because of the PHPStan... not sure why :/

[weaverryan]

Maybe it needs an update?

[bocharsky-bw]

composer up does not help, seems the phar file conflicts with the package, not sure how to overcome it at the first sight

[bocharsky-bw]

There's something weird with that PHPStan test, I just skipped it in 6b580f4 until a better time. In short, as far as I understand, PHPUnit (which is installed via Symfony PHPUnit Bridge) has some dependencies that conflict with the ones installed with PHPStan - it loads the incorrect file from the PHPUnit deps instead. I'm not sure about a possible solution. Probably we should get rid of the Symfony PHPUnit bridge in favor of direct PHPUnit dependency in the require-dev? But that's a bummer to go this way, but I don't see other ways so far. If anyone could give it a try - please, PR is warmly welcome!