Bump php-cs-fixer to v2.19.0

[stronk7]

That version supports PHP8 and is the last one
before jumping to v3 that comes with huge changes.

This will help in the progress towards PHP8 support happening @ #94

[stronk7]

And it works ok with PHP8 too, just in case (apart from current CI tests using it):

$ make
php build/php-cs-fixer.phar fix -v || true
PHP CS Fixer 2.19.0 Testament by Fabien Potencier and Dariusz Ruminski (d5b8a9d)
Runtime: PHP 8.0.3
Loaded config default from "/Users/stronk7/git_moodle/moodle-plugin-ci/.php-cs-fixer.php".
.........................................................................................................................................
Legend: ?-unknown, I-invalid file syntax (file ignored), S-skipped (cached or empty file), .-no changes, F-fixed, E-error

Fixed all files in 3.147 seconds, 14.000 MB memory used

[stronk7]

Aha, there is a new rule no_alias_language_construct_call in the Symfony rules. I think it's ok to keep it enabled, so fixing the die()uses.

[kabalin]

All looks good, thanks @stronk7

[stronk7]

Thanks!