assetPrefix and pathPrefix can't works seamlessly.

[jiusanzhou]

Recently, I'm building landing pages for a github repository, and which deployed in gh-pages. So I must set pathPrefix as the repo name, then I can visit the page by url: https://MYDOMAIN/REPONAME

When I use cdn.jsdelivr.net as a CDN provider, setting the assetPrefix as https://cdn.jsdelivr.net/gh/USERNAME/REPONAME@gh-pages. Things won't work well.

I think we should make this more configurable. In normal situation, ask users to set assetPrefix endswith pathPrefix manually.

Change the getPublicPath function in get-public-path.ts like bellow:

export const getPublicPath = ({
  assetPrefix,
  pathPrefix,
  prefixPaths,
}: {
  assetPrefix?: string
  pathPrefix?: string
  prefixPaths: boolean
}): string => {
  if (prefixPaths && (assetPrefix || pathPrefix)) {
    const normalized = assetPrefix || pathPrefix // assetPrefix only or pathPrefix

    return isURL(normalized) ? normalized : `/${normalized}`
  }

  return ``
}