Fix content: replace broken AI agents link with working resource

src/data/roadmaps/ai-engineer/content/ai-agents@9XCxilAQ7FRet7lHQr1gE.md

@@ -5,5 +5,5 @@ In AI engineering, "agents" refer to autonomous systems or components that can p
 Visit the following resources to learn more:
 
 - [@article@Building an AI Agent Tutorial - LangChain](https://python.langchain.com/docs/tutorials/agents/)
-- [@article@AI Agents and Their Types](https://play.ht/blog/ai-agents-use-cases/)
+- [@article@AI Agents and Their Types](https://www.digitalocean.com/resources/articles/types-of-ai-agents)
 - [@video@The Complete Guide to Building AI Agents for Beginners](https://youtu.be/MOyl58VF2ak?si=-QjRD_5y3iViprJX)