License in package.json

[LICENSE ](https://github.com/tuchk4/storybook-readme/blob/master/LICENSE) of github is MIT, and [package.json](https://github.com/tuchk4/storybook-readme/blob/master/package.json) is in ISC. 
It seems that the license of package.json need to be updated to MIT.

https://github.com/tuchk4/storybook-readme/blob/master/package.json : 
```
"license": "ISC"
```