Adding Update Script to package.json

[adrianmcli]

Hey @arunoda, great work! I was thinking, since many people may not know yeoman very well and may not feel comfortable using it. Maybe it would help to put yo react-cdk:update inside package.json as an NPM script, so people could simply type:

npm run update

Thoughts?

[arunoda]

Hmm. I think that's too small for a NPM script.
Eventually, they'll get used to yo.
Since they've to use yo react-cdk my-comp when creating the component.

And we are planning to build a service which helps this process. See #7

[adrianmcli]

Sounds good!