Updated $fillable in order to fill title, content and authorName

AddedFillable_BlogPost.php

<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Factories\HasFactory;
use Illuminate\Database\Eloquent\Model;

class BlogPost extends Model
{
    use HasFactory;

    protected $fillable = [
        'title',
        'content',
        'author_name',
    ];
}