amend neo4j connection instruction in the local dev example (#311)

Author: badmonster0

examples/docs_to_kg/README.md

@@ -40,6 +40,12 @@ python main.py cocoindex update
 ### Browse the knowledge graph
 
 After the knowledge graph is build, you can explore the knowledge graph you built in Neo4j Browser.
+
+For the dev enviroment, you can connect neo4j browser using credentials:
+- username: `neo4j`
+- password: `cocoindex`
+which is pre-configured in the our docker compose [config.yaml](https://raw.githubusercontent.com/cocoindex-io/cocoindex/refs/heads/main/dev/neo4j.yaml).
+
 You can open it at [http://localhost:7474](http://localhost:7474), and run the following Cypher query to get all relationships:
 
 ```cypher