Link for running the development server in line 84 of README.md is broken.

Current text contains a second documentation link that returns a 404 error:
https://langchain-ai.github.io/langgraph/how-tos/local-studio/#run-the-development-server

This should be replaced with the correct documentation URL:
https://langchain-ai.github.io/langgraph/cloud/how-tos/studio/quick_start/#local-development-server