sp-dev-fx-webparts/samples/react-my-events/config/serve.json

{
  "$schema": "https://developer.microsoft.com/json-schemas/core-build/serve.schema.json",
  "port": 4321,
  "https": true,
  "initialPage": "https://vtsp.sharepoint.com/sites/SPFXTutorial/_layouts/15/workbench.aspx"
}