Validate content hashes in npm with postpublish script

[geotrev]

Issue:

Although it's already decently clear that the b64 content hashes created for cdn-ready content is going to be correct.

Solution:

There should be a postpublish node script which correctly validates the content hashes at @latest for umd content in the dist/ folder. Any CDN, not just jsdelivr, won't have propagated the new content yet, so querying the npm registry directly is preferred.