feat: Cleaner support for NextJS

[nicholas-codecov]

          Given we have a specific package now, we can also expose a wrapper API like `@next/bundle-analyzer` does: https://www.npmjs.com/package/@next/bundle-analyzer

So the API would be export default withCodecov(...)

We should just make sure it's compatible with https://github.com/cyrilwanner/next-compose-plugins.

Originally posted by @AbhiPrasad in #157 (comment)