Fix bind json-api to facade (app container)

Author: d8vjork

src/JsonApiServiceProvider.php

@@ -7,6 +7,7 @@
 use Illuminate\Support\ServiceProvider;
 use Illuminate\Testing\TestResponse;
 use SkoreLabs\JsonApi\Builder as JsonApiBuilder;
+use SkoreLabs\JsonApi\Support\JsonApi;
 use SkoreLabs\JsonApi\Testing\TestResponseMacros;
 
 class JsonApiServiceProvider extends ServiceProvider
@@ -36,6 +37,10 @@ public function register()
 
         $this->mergeConfigFrom(__DIR__.'/../config/json-api.php', 'json-api');
 
+        $this->app->singleton('json-api', function () {
+            return new JsonApi();
+        });
+
         $this->registerTestingMacros();
     }