minor update needed for Readme.md

[jcpoyser]

incorrect github username and directory name causes instruction to fail

git clone https://github.com/jthurst/platform-event-node-example.git
cd platform-event-node-example
npm install

should be:

git clone https://github.com/jthurst01/platform-events-node-example.git
cd platform-events-node-example
npm install