Remove BioChanged event which is no longer used since beta 8 (#2196)

framework/core/src/User/Event/BioChanged.php

@@ -1,35 +0,0 @@
-<?php
-
-/*
- * This file is part of Flarum.
- *
- * For detailed copyright and license information, please view the
- * LICENSE file that was distributed with this source code.
- */
-
-namespace Flarum\User\Event;
-
-use Flarum\User\User;
-
-class BioChanged
-{
-    /**
-     * @var User
-     */
-    public $user;
-
-    /**
-     * @var User
-     */
-    public $actor;
-
-    /**
-     * @param User $user
-     * @param User $actor
-     */
-    public function __construct(User $user, User $actor = null)
-    {
-        $this->user = $user;
-        $this->actor = $actor;
-    }
-}