Update MySQL PDO compression attribute for PHP 8.5 compatibility

[phpukr]

File affected: core/classes/database/pdo/connection.php

Currently, FuelPHP sets the PDO compression attribute using PDO::MYSQL_ATTR_COMPRESS.
Starting from PHP 8.5, this constant is deprecated and replaced by Pdo\Mysql::ATTR_COMPRESS.

Proposed solution to maintain compatibility with both PHP <=8.4 and PHP 8.5+:

// enable compression if needed
if (!empty($this->_config['connection']['compress']))
{
    if (class_exists('\Pdo\Mysql')) {
        // PHP 8.5+
        $this->_config['attrs'][\Pdo\Mysql::ATTR_COMPRESS] = true;
    } elseif (defined('\PDO::MYSQL_ATTR_COMPRESS')) {
        // PHP <= 8.4
        $this->_config['attrs'][\PDO::MYSQL_ATTR_COMPRESS] = true;
    }
}