Fix #98 and remove package-lock.json

[kopax]

This fix:

• Upgrade node-fetch to >= 2.3.0 to fix semantic-release users that use styled-components #98
• test: npm test was failing due to jest.testURL not specified in package.json
• lockfile: lock file should not be used for modules, only for application. This can lead to potential errors. It was remove in profit of .npmrc telling this does not need a package-lock.json

[jacobp100]

Could you update the yarn lock file? 😀

(I think you can just run yarn to do it)

[kopax]

$ yarn
bash: yarn: command not found
$ npx yarn
npx: installed 1 in 5.468s
yarn install v1.12.3
# ... zzz
To github.com:kopax/css-to-react-native.git
   c62fdfb..5bb1433  master -> master

All good

[stevemao]

Is this needed when you have package-lock=false in .npmrc?

[mxstbr]

Let's ship it @jacobp100?!