🐛 fixes error in windows when execute npm run test

[shangyilim]

this fixes an issue where npm run test will cause an error in windows machine.

PS C:\Projects\learnyounode> npm run test

> [email protected] test C:\Projects\learnyounode
> npm run lint && ./node_modules/.bin/workshopper-adventure-test

npm WARN invalid config loglevel="notice"

> [email protected] lint C:\Projects\learnyounode
> standard

'.' is not recognized as an internal or external command,
operable program or batch file.
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! [email protected] test: `npm run lint && ./node_modules/.bin/workshopper-adventure-test`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the [email protected] test script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     C:\Users\chris\AppData\Roaming\npm-cache\_logs\2017-10-05T12_40_20_145Z-debug.log