Misreads React version

[jorisw]

I am running React 16.13.1, but line 4 in src/usePolling.js makes it think it's a version that doesn't support hooks:

  4 |   const version = React.version.split('-');
  5 |   if (version[0] < '16.7.0') {
> 6 |     throw new Error('Hooks are only supported in React 16.7.0-alpha release or above');
  7 |   }