Change attribution for the Haskell Beginners 2022 course

Hi!

Thanks for adding my course to the GHCup starting page

I've noticed that it's currently written on the website that the course is made by Kowainik. I made this course completely on my own and I'm no longer a member of Kowainik. So I would like to change the attribution of the course to my name.

Thanks!

merged

merged and deployed: https://www.haskell.org/ghcup/steps/#how-to-learn-haskell-proper

That was super fast! Thanks a lot, @maerwald