sdk-for-dart/docs/examples/webhooks/update.md

import 'package:dart_appwrite/dart_appwrite.dart';

Client client = Client()
    .setEndpoint('https://<REGION>.cloud.appwrite.io/v1') // Your API Endpoint
    .setProject('<YOUR_PROJECT_ID>') // Your project ID
    .setKey('<YOUR_API_KEY>'); // Your secret API key

Webhooks webhooks = Webhooks(client);

Webhook result = await webhooks.update(
    webhookId: '<WEBHOOK_ID>',
    name: '<NAME>',
    url: '',
    events: [],
    enabled: false, // (optional)
    tls: false, // (optional)
    authUsername: '<AUTH_USERNAME>', // (optional)
    authPassword: '<AUTH_PASSWORD>', // (optional)
);