Support URL source / pkg.pr.new

It would be great to support URL sources, most notably for https://github.com/stackblitz-labs/pkg.pr.new. For example, in https://github.com/mui/base-ui/pull/4761 we are experimenting with https://x.com/cnakazawa/status/2052640752820424882. We have a new version of the npm package at https://pkg.pr.new/mui/base-ui/@base-ui/react@4761, having this capability supported in packagephobia would make it easier to appreciate the package size increase cost/tradeoff.