It is just a warning you can ignore it.
it is requested by a third-party dependency not by Laravel itself. So when this dependency gets updated by its mantainer this message will disappear.
To know which dependency requires it you can run:
$ composer why phpunit/php-token-stream
Which outputs:
phpunit/php-code-coverage 7.0.10 requires phpunit/php-token-stream (^3.1.1)
And phpunit/php-code-coverage is required by phpunit/phpunit which is required by Laravel.
So probably on a next update to PHPUnit this message will vanish. By now no need to worry about it.