wireprotov2: define response data as CBOR Previously, response data was defined as a stream of bytes. We had the option to declare it as CBOR using a frame flag. We've converged all wire protocol commands exposed on version 2 to CBOR. I think consistency is important. The overhead to encoding things with CBOR is minimal. Even a very large bytestring can be efficiently encoded using an indefinite length bytestring. Now, there are limitations with consumers not being able to efficiently stream large CBOR values. But these feel like solvable problems. This commit removes the "is CBOR" frame flag from command response frames and defines the frame as always consisting of a stream of CBOR values. The framing protocol media type has been bumped to reflect this BC change. Differential Revision: https://phab.mercurial-scm.org/D3382