remove listener & add version320 migration

database/migrations/2020_12_02_064933_update_crater_version_320.php

@@ -0,0 +1,31 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+use Crater\Setting;
+
+class UpdateCraterVersion320 extends Migration
+{
+    const VERSION = '3.2.0';
+
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Setting::setSetting('version', static::VERSION);
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        //
+    }
+}