Downstream packages cannot resolve latest cbor version due to non-semantic versioning of cbor

[ThisIsMissEm]

In the cose gem, they depended on cbor ~> 0.5.9 which doesn't seem to resolve correctly to 0.5.9.8 since ~> is a semantic version comparator, and this project isn't using semantic versioning.

It may be an idea to adopt semantic versioning which seems to be what rubygems recommends: https://guides.rubygems.org/patterns/#semantic-versioning (in their words "urges developers"), since this would avoid issues like this for cbor and other downstream dependents.