Update styled components for React 16 (#3187)
Update styled components for React 16 (#3187)

Next 4 only works with React 16, so for this example to work we need an update.
BlancheXu/test,azukaru/next.js,flybayer/next.js,zeit/next.js,BlancheXu/test,BlancheXu/test,flybayer/next.js,callumlocke/next.js,flybayer/next.js,JeromeFitz/next.js,JeromeFitz/next.js,azukaru/next.js,zeit/next.js,azukaru/next.js,flybayer/next.js,azukaru/next.js,zeit/next.js,JeromeFitz/next.js,JeromeFitz/next.js