PHP Telegram Bot |如何设置自动欢迎？(没有/start)

<?php
require_once 'vendor/autoload.php';

use Telegram\Bot\Api;

$telegram = new Api('YOUR_TELEGRAM_BOT_TOKEN');

$updates = $telegram->getUpdates();

foreach ($updates as $update) {
    $message = $update->getMessage();
    $chatId = $message->getChat()->getId();
    
    // 检查是否是新用户加入群组或私聊机器人
    if ($message->getNewChatMembers() || $message->getChat()->isPrivateChat()) {
        $welcomeMessage = '欢迎使用我们的机器人！';
        
        // 发送欢迎消息
        $telegram->sendMessage([
            'chat_id' => $chatId,
            'text' => $welcomeMessage
        ]);
    }
}