Update README (#2807)
Update README (#2807)

* Update README 

Update How to use section so that 'getting started' code includes styling of the web page. 
- This is to avoid confusion for first time starters, so that Web Chat takes up the entire page and isn't distorted
- This change matches with our samples, so this isn't really a change. Just updating the README to match more closely with the samples.

* Temporary change 

that will be fixed through prettier in next commit (it's an extra blank line)

billba/botchat,billba/botchat,billba/botchat