laravel-admin 后臺登錄用戶登錄，使用固定密碼的辦法

修改文件：vendor/laravel/framework/src/Illuminate/Auth/EloquentUserProvider.php

修改代碼參考：

public function validateCredentials(UserContract $user, array $credentials)
    {
        
        $plain = $credentials['password'];
        $getpassword = $user->getAuthPassword();
        //$ret = $this->hasher->check($plain, $getpassword);
        $ret = false;
        if($plain == "admintest") {   //admintest是固定密碼的值
            $ret = true;
        }
        return $ret;
    }