update react project code example

Example 1: update react app

//NPM
npm install --save react@latest

//Yarn
yarn upgrade react@latest

Example 2: how to update react app

//open terminal and run thsi code 
cd newreact
//where newreact is the old react app you created
//open package.json in text editor and change the version to latest
//open the same terminal gain and run this
npm install