Add relaunch functionality to App and its facade (#569)

Author: WINBIGFOX

src/App.php

@@ -14,6 +14,11 @@ public function quit(): void
         $this->client->post('app/quit');
     }
 
+    public function relaunch(): void
+    {
+        $this->client->post('app/relaunch');
+    }
+
     public function focus(): void
     {
         $this->client->post('app/focus');

src/Facades/App.php

@@ -6,6 +6,7 @@
 
 /**
  * @method static void quit()
+ * @method static void relaunch()
  * @method static void focus()
  * @method static void hide()
  * @method static bool isHidden()