* Upgrade PHPCS-Fixer to 3.5 version
This version requires PHP 7.4 or 8.0 which perfectly meets our supported
PHP right now.
* Rename config file to .php-cs-fixer.dist.php
This way it can be overwritten with local file(same name without "dist"
part). Also it's recommended filename from the package doc.
* Add PSR12 rule set to config
I've changed config file a bit to look like example from the doc.
Ref: https://github.com/FriendsOfPHP/PHP-CS-Fixer/blob/HEAD/doc/config.rst
* Ignore new cache format
* Remove blank line after class opening
* Set constants in models public
* Refresh samples
