v0.2.1

Fixed

• The hex package now declares livery and h2 as requirements. Earlier
  packages were built from a tree with _checkouts, which dropped them
  (0.2.0 declared only gpb), so livery_grpc could not be installed
  from hex on its own. make publish builds from a clean export of HEAD
  and checks the requirements.

Changed

• Require livery ~> 0.10.2 (any 0.10.x from 0.10.2). barrel_mcp and
  barrel_a2a are no longer fetched or locked: livery made them
  optional dependencies.