Update README.md

On creating a new Okta object the readme just states to enter 'your-domain,' so I passed '<company>.okta.com' (the full subdomain).  Doing this causes the request in NetworkAbstraction to generate a hostname of <company>.okta.com.okta.com which causes Node to throw a very obscure SSL error on every request.  Updated readme to make this explicitly clear so other people don't make the same dumb mistake.
Update README.md

Fixed copy and paste derp.
Merge pull request #2 from aradnom/master

Readme fix