Broken link in README

[rlvoyer]

The following section of the README references the agents projects module, but the associated link is broken:

Like default use case proposed in [LangGraph blog](https://blog.langchain.dev/langgraph/), We have ported [AgentExecutor](https://github.com/langchain-ai/langchain/blob/master/libs/langchain/langchain/agents/agent.py) implementation from [langchain](https://github.com/langchain-ai/langchain/) using LangGraph4j. In the [agents](https://github.com/bsorrentino/langgraph4j/blob/main/agents) project's module, you can the complete working code with tests. Feel free to checkout and use it as a reference. Below you can find a piece of code of the AgentExecutor to give you an idea of how is has built in langgraph style.