PHP CSV file Upload Parse error: syntax error, unexpected '?', expecting variable error

I was working on CSV file upload & it is working fine on local server (php - 7.1) but it gives error on server which has php version 7.2

I have tested the code in php 7.2 version on local server it is working fine and also checked vendor folder still the code is not working on server

This is the message I am getting-

"message": "Parse error: syntax error, unexpected '?', expecting variable (T_VARIABLE)", "exception": "Symfony\Component\Debug\Exception\FatalThrowableError", "file": "/var/www/html/Franchisee_laravel/vendor/symfony/css-selector/XPath/Extension/AttributeMatchingExtension.php",

via Chebli Mohamed