[swr-openapi] react peer dependencies

[masterpiece911]

Hello 👋🏼

I'm an ardent user of openapi-typescript in my projects, and I would love to try and evaluate swr-openapi as well. As I'm on long-term maintenance of a few of these projects, I am unable to bump dependencies on a few of them, but would like to gradually adopt swr-openapi if I determine it a significant improvement over my previous data-fetching strategies.

One major blocker for this is the strict(er) peer dependency at 18 | 19 for React. This is surprising for me, as the peer dependency for useSWR itself is quite a lot more generous at 16 onwards. As I've struggled to identify a library reason for this restriction, I wanted to ask why swr-openapi is stricter than useSWR here, given that it is just a light wrapper on top.