remove listener & add version320 migration

app/Listeners/Updates/v3/Version320.php

@@ -1,32 +0,0 @@
-<?php
-
-namespace Crater\Listeners\Updates\v3;
-
-use Crater\Listeners\Updates\Listener;
-use Crater\Events\UpdateFinished;
-use Crater\Setting;
-use Crater\Currency;
-use Artisan;
-
-class Version320 extends Listener
-{
-    const VERSION = '3.2.0';
-
-    /**
-     * Handle the event.
-     *
-     * @param UpdateFinished $event
-     * @return void
-     */
-    public function handle(UpdateFinished $event)
-    {
-        if ($this->isListenerFired($event)) {
-            return;
-        }
-
-        Artisan::call('migrate', ['--force' => true]);
-
-        // Update Crater app version
-        Setting::setSetting('version', static::VERSION);
-    }
-}