[README.md] Error in sample code at 'SSR with Next.js'

[zeroslope]

Sample code at '#ssr-with-nextjs'
https://github.com/zeit/swr/blob/master/README.md#ssr-with-nextjs
https://github.com/zeit/swr/blame/master/README.md#L359-L362

current code

App.getInitialProps = async getInitialProps () {
  const data = await fetcher('/api/data')
  return { data }
}

it may be

App.getInitialProps = async function getInitialProps () {
  const data = await fetcher('/api/data')
  return { data }
}

or

App.getInitialProps = async () => {
  const data = await fetcher('/api/data')
  return { data }
}