update changelog deploy button url

Author: vy-ton

src/content/changelog/durable-objects/2025-04-07-durable-objects-free-tier.mdx

@@ -11,7 +11,7 @@ Durable Objects can now be used with zero commitment on the [Workers Free plan](
 
 Durable Objects let you build stateful, serverless applications with millions of tiny coordination instances that run your application code alongside (in the same thread!) your durable storage. Each Durable Object can access its own SQLite database through a [Storage API](/durable-objects/best-practices/access-durable-objects-storage/). A Durable Object class is defined in a Worker script encapsulating the Durable Object's behavior when accessed from a Worker. To try the code below, click the button: 
 
-[![Deploy to Cloudflare](https://deploy.workers.cloudflare.com/button)](https://deploy.workers.cloudflare.com/?url=https://github.com/cloudflare/templates/tree/staging/TODO)
+[![Deploy to Cloudflare](https://deploy.workers.cloudflare.com/button)](https://deploy.workers.cloudflare.com/?url=https://github.com/cloudflare/templates/tree/staging/hello-world-do-template)
 
 ```js
 import { DurableObject } from "cloudflare:workers";