Symfony version(s) affected: 5.3.2 (at least)

Description
Routes with an UTF-8 parameter name can't be found.

How to reproduce
In YAML

informes:
    path: /informes/{año}
    controller: App\Controller\InformesController::anual

or attributes

#[Route("/informes/{año}", name: "informes")]
public function anual(string $año)
{
    dd($año);
}

Possible Solution
I don't know, I suppose that is a regression because I remember using this on Symfony 2 many years ago.

Additional context
I have tried with YAML, annotations and attributes and only in the last 5.3 version.
Any route with UTF-8 characters works fine, only fails with UTF-8 parameters name.
The routing.yaml have

framework:
    router:
        utf8: true

And add utf8: true to route options doesn't work either