Laravel Nova日期字段始终提交null

Schema::create('posts', function (Blueprint $table) {
    $table->id();
    $table->string('title');
    $table->date('publish_date');
    $table->timestamps();
});

namespace App\Nova;

use Laravel\Nova\Fields\Date;
use Laravel\Nova\Resource;

class Post extends Resource
{
    public function fields(Request $request)
    {
        return [
            Text::make('Title'),
            Date::make('Publish Date', 'publish_date')
                ->rules('required'),
        ];
    }
}

namespace App\Http\Controllers;

use App\Models\Post;
use Illuminate\Http\Request;

class PostController extends Controller
{
    public function store(Request $request)
    {
        $validatedData = $request->validate([
            'publish_date' => 'required|date',
        ]);

        Post::create($validatedData);

        return redirect()->route('posts.index');
    }
}