Fails with private repos, does not respect DENO_AUTH_TOKENS

Per the title, this will fail on files that are from private repositories. The files load without issue in Deno thanks to [DENO_AUTH_TOKENS](https://deno.land/manual@v1.31.2/basics/modules/private).

Looking into a bit it seems this tool handles no auth whatsoever in fetching https modules here https://github.com/denoland/eszip/blob/1086f52450a569987b61849700d6e3f826d12be1/lib/loader.ts#L43

Specifically this is failing for me as a user of Supabase edge functions (which run on Deno Deploy). I can't deploy my functions because they're bundled using this tool and they have deps in private repositories.