feat: upgrade to node 18

.github/workflows/host.yml

@@ -19,7 +19,7 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [16.x]
+        node-version: [18.x]
 
     steps:
       - name: Get code

src/index.ts

@@ -4,6 +4,7 @@ import { registerErrorHandlers } from './events/error.js';
 import guildMemberAdd from './events/guildMemberAdd.js';
 import interactionCreate from './events/interactionCreate.js';
 import ready from './events/ready.js';
+import './fetch-polyfill';
 
 export const client = new Client({
   intents: [GatewayIntentBits.Guilds, GatewayIntentBits.GuildMembers],