Rebuild CI and fix CS

[bocharsky-bw]

After some changes upstream in GitHub CI config: SymfonyCasts/.github#2

[bocharsky-bw]

Seems the lowest support version here is 7.4 so I had to downgrade the PHP version for PHP CS Fixer to 7.4 as well to avoid fixing:

-throw new UnsupportedUserException(sprintf('Instances of "%s" are not supported.', \get_class($user)));
+throw new UnsupportedUserException(sprintf('Instances of "%s" are not supported.', $user::class));

that is not supported by PHP 7.4

[weaverryan]

Thanks Victor!