URL port error in README

[NanaXiong00]

Describe the issue:
Start the webapp server, the port is displayed as 5137, but in the README(GitHub Codespaces, VS Code Dev Containers and Local Environment) it shows to open the URL http://localhost:4280 .

Suggestion:
Update 4280 to 5173 in README.

@jongio and @manekinekko for notification.