[8.x] Change Wormhole to use the Date Factory

[kalfheim]

I wanted to use CarbonImmutable by default in an app I'm building, and got caught up in a wormhole issue when trying to travel into the future.

Basically, this example currently doesn't work as expected:

<?php

namespace Tests\Feature;

use Carbon\CarbonImmutable;
use Illuminate\Support\Facades\Date;
use Tests\TestCase;

class ExampleTest extends TestCase
{
    public function testItTravelsInTime()
    {
        Date::use(CarbonImmutable::class);

        $this->travel(10)->days();

        dump(now()); // Incorrectly dumps the current time
    }
}

This PR fixes the issue by making sure the Wormhole class references Illuminate\Support\Facades\Date facade instead of Illuminate\Support\Carbon.

Also added a test to make sure it works as expected.