Read me validation check before publishing collection warning -> error?

[mvgadagi]

If an author publishes a collection without a README, it is currently flagged as a warning during npm run validate. We can considering changing this to an error, as providing a README should be mandatory. This is a recommended best practice that helps users understand the collection when it is opened in the extension.

[gblanc-1a]

Indeed I believe it should be an error for new collection (if we are able to detect it) but it was put as a warning for all the existing collections without readme. But then again since validation happens only at publish time we could indeed transform it as an error