gh_url: GitHub URL of a package to check, or NULL to check the package in the current directory.
platforms: Platforms to use, a character vector. Use NULL to select from a list in interactive sessions. See rhub_platforms().
r_versions: Which R version(s) to use for the platforms that supports multiple R versions. This argument is not implemented yet.
branch: Branch to use to run R-hub. Defaults to the current branch if gh_url is NULL. Otherwise defaults to "main". Note that this branch also need to include the rhub.yaml workflow file.