fixes #1 JSON Server update

[vitorreis]

Fixes this problem:

npm run dev

> [email protected] dev /Users/v.reis/workspace/cypress-tutorial-build-todo-starter
> concurrently "npm run watch" "npm run serve"

[0]
[0] > [email protected] watch /Users/v.reis/workspace/cypress-tutorial-build-todo-starter
[0] > webpack --watch
[0]
[1]
[1] > [email protected] serve /Users/v.reis/workspace/cypress-tutorial-build-todo-starter
[1] > json-server db.json
[1]
[1] json-server requires at least version 4 of Node, please upgrade
[1] npm
[1]  ERR! code ELIFECYCLE
[1] npm
[1]  ERR! errno 1
[1] npm ERR!
[1]  [email protected] serve: `json-server db.json`
[1] npm ERR! Exit status 1
[1] npm ERR!
[1]
[1] npm ERR! Failed at the [email protected] serve script.
[1] npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
[1]
[1] npm ERR! A complete log of this run can be found in:
[1] npm ERR!