v2.0.0

Breaking changes

Make Array and Map methods on Decoder

The package-level Array and Map functions are gone.
Call them on the decoder instead: jsoncap.Array(d, prior, ...) becomes
d.Array(prior, ...), and jsoncap.Map(d, prior, ...) becomes
d.Map(prior, ...). The import path moves to github.com/cplieger/jsoncap/v2.

Changed

• [breaking] Make Array and Map methods on Decoder