Updated syntax for supporting caches in Eloquence

Post.php

<?php

use Eloquence\Behaviours\CountCache\CountedBy;
use Eloquence\Behaviours\CountCache\HasCounts;
use Illuminate\Database\Eloquent\Model;

class Post extends Model {
    use HasCounts;
    
    #[CountedBy]
    public function author(): BelongsTo
    {
        return $this->belongsTo(Author::class);
    }
}