Saved date does not show up in the form - laravel

Question

I'm using laravel livewire and I've created a page that you can select a date for when you want the post
to publish. When I create a new post and save the date then it saves fine in the database, but if I try
to edit the post and change the date the date that I saved in the database isn't showing in the form.
Here is my code.
My EditPost.php
<?php
namespace App\Http\Livewire;
use App\Models\Post;
use Livewire\Component;
class EditPost extends Component
{
public $name;
public $publishDate;
public Post $post;
public function mount(Post $post)
{
$this->name = $post->name;
$this->publishDate = $post->publish_date;
}
public function render()
{
return view('livewire.edit-post');
}
}
and this is my edit.blade.php
<div>
<div class="mt-10 sm:mt-0">
<div class="md:grid md:grid-cols-3 md:gap-6">
<div class="md:col-span-1">
<div class="px-4 sm:px-0">
<h3 class="text-lg font-medium leading-6 text-gray-900">Edit Post</h3>
</div>
</div>
<div class="mt-5 md:mt-0 md:col-span-2">
<div class="form">
<div class="shadow overflow-hidden sm:rounded-md">
<div class="px-4 py-5 bg-white sm:p-6">
<div class="grid grid-cols-6 gap-6">
<div class="col-span-6 sm:col-span-3">
<label for="name" class="block text-sm font-medium leading-5 text-gray-700">Name</label>
<input id="name" wire:model="name" class="#error('name') border border-red-500 #enderror mt-1 form-input block w-full transition duration-150 ease-in-out sm:text-sm sm:leading-5">
#error('name')
<small>
<div class="text-red-500">{{ $message }}</div>
</small>
#enderror
</div>
<div class="col-span-6 sm:col-span-4">
<label for="publish_date" class="block text-sm font-medium leading-5 text-gray-700">Publish Date</label>
<input id="publish_date" wire:model="publishDate" type="date" class="mt-1 form-input block w-full transition duration-150 ease-in-out sm:text-sm sm:leading-5">
</div>
</div>
</div>
<div class="px-4 py-3 bg-gray-50 text-right sm:px-6">
<button wire:click="editPost" class="py-2 px-4 border border-transparent text-sm leading-5 font-medium rounded-md text-white bg-indigo-600 shadow-sm hover:bg-indigo-500 focus:outline-none focus:shadow-outline-blue active:bg-indigo-600 transition duration-150 ease-in-out">
Save
</button>
</div>
</div>
</div>
</div>
</div>
</div>
</div>