Score check should verify that package can actually be loaded

[Gozala]

Hi Team,

We would like to ensure that our packages work with cdn.skypack.dev but sadly we run into cases where e.g. https://www.skypack.dev/view/nft.storage package worked fine in 3.x but fails to load in 4.x

Failure to even load is not reflected in the package score.

It would be really great to have a github action that we can add to our workflows that can verify that package is compatible with https://cdn.skypack.dev so we can avoid merging changes that break support.

I think it also would really help to see which packages are actually loadable on https://www.skypack.dev/ because current package scores don't reflect that.