docs: update README

[throwaway00]

This change should result in this account being invited to the maintainers team.

[gatsbot]

Holy buckets, @throwaway00 — we just merged your first PR to Gatsby! 💪💜

Gatsby is built by awesome people like you, and we’d love to say “thanks” in two ways:

1. We just invited you to join our team of maintainers on GitHub. You’ll receive an email shortly asking you to confirm. By joining the team, you’ll be able to label issues, review pull requests, and merge approved pull requests.
2. We’d like to send you some Gatsby swag. As a token of our appreciation, you can go to the Gatsby Swag Store and log in with your GitHub account to get a coupon code good for one free piece of swag. (Currently we’ve got a couple t-shirts available, plus some socks that are really razzing our berries right now.)

If there’s anything we can do to help, please don’t hesitate to reach out to us: just mention @gatsbyjs/inkteam on GitHub or tweet at @gatsbyjs and we’ll come a-runnin’.

Thanks again!

[jlengstorf]

🎉 🎉 🎉

[jlengstorf]