$s3 = new S3Client([
            'version' 	=> 'latest',
            'region'  	=> 'ru-1a',
            'credentials' => [
                'key'	=> '...',
                'secret' => '...',
            ],
            'endpoint' => 'https://s3.selcdn.ru'
]);

$s3->putObject([
                'Bucket'     => 'code-reffection-com-codes',
                'Key'        => '...',
                'Body' => $'...',
]);