Add migration to change webhook URL max length to 511 characters

Fixes #76

migrations/2024_12_30_increase_webhook_url_length.php

@@ -0,0 +1,24 @@
+<?php
+
+/*
+ * This file is part of fof/webhooks.
+ *
+ * Copyright (c) FriendsOfFlarum.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Schema\Builder;
+
+return [
+    'up' => function (Builder $schema) {
+        $schema->table('webhooks', function (Blueprint $table) {
+            $table->string('url', 511)->change();
+        });
+    },
+    'down' => function (Builder $schema) {
+        // no need to revert this change
+    },
+];