low version laravel migrate in mysql

AppServiceProvider.php

//Illuminate\Database\QueryException]                                                                                                                                                 
//  SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 767 bytes (SQL: alter table `users` add unique `users_email_unique`(`email`)) 

use Illuminate\Support\Facades\Schema;

public function boot()
{
    Schema::defaultStringLength(191);
}