PHPCS: function dirname() detected with dynamic parameter directly from user input

I am having code vulnerability in a opensource project i am working on.

The vulnerability is: Filesystem function dirname() detected with dynamic parameter directly from user input.

Full code of my class is available here

What i am trying is getting website url with following two methods,

//get protocol whether it is secured or plain
public static function websiteProtocol()
{
    return (isset($_SERVER['HTTPS']) && (!empty($_SERVER['HTTPS']) || $_SERVER['HTTPS'] !== 'off') ? 'https' : 'http');
}

And then, get url like this,

public static function websiteUrl()
{
    return self::websiteProtocol() . '://' . $_SERVER['HTTP_HOST'] . dirname($_SERVER['PHP_SELF']) . '/';
}

Now, as i am using dirname() with a $_SERVER variable, the PHP code sniffer throws a high vulnerability i mentioned above.

How to resolve this? I have tried to create $dir = dirname($_SERVER['PHP_SELF']); and replace it in websiteUrl method but it is the same error as i am still using $_SERVER['PHP_SELF'] as a parameter of dirname() method.

I cant remove the method websiteUrl as it fetches the website url that allows my project to be deployed anywhere with just one modification in config file.

I have also created issue on my repository

Any help here or direct PR on my repo appreciated.