implement DeferrableProvider

$defer has been deprecated after laravel 5.8
(https://laravel.com/docs/5.8/upgrade#deferred-service-providers)

and removed after laravel 6.x
(laravel/framework#27505)

(cherry picked from commit 99cc41e)

Author: kon-shou

src/IdeHelperServiceProvider.php

@@ -15,22 +15,16 @@
 use Barryvdh\LaravelIdeHelper\Console\GeneratorCommand;
 use Barryvdh\LaravelIdeHelper\Console\MetaCommand;
 use Barryvdh\LaravelIdeHelper\Console\ModelsCommand;
+use Illuminate\Contracts\Support\DeferrableProvider;
 use Illuminate\Support\ServiceProvider;
 use Illuminate\View\Engines\EngineResolver;
 use Illuminate\View\Engines\PhpEngine;
 use Illuminate\View\Factory;
 use Illuminate\View\FileViewFinder;
 
-class IdeHelperServiceProvider extends ServiceProvider
+class IdeHelperServiceProvider extends ServiceProvider implements DeferrableProvider
 {
 
-    /**
-     * Indicates if loading of the provider is deferred.
-     *
-     * @var bool
-     */
-    protected $defer = true;
-
     /**
      * Bootstrap the application events.
      *