Testing local deployments for GitHub pages doesn't work since no `basePath` can be set

Description

serve is great! However, there are a number of scenarios that can't be tested with it, for example vite or sveltekit builds with basePath set or deployments to GitHub pages which also require a basePath.

I found this old issue but I think there are more than enough usecases, it's not just an "edge case", so thought it's worth bringing up again: Related to https://github.com/vercel/serve/issues/184

Library version

14.2.1

Node version

v18.13.0