v0.2.0

Added

• A service registration may carry a config, delivered to every callback of that service as the context's config, so a service that serves one backend carries its handle without a global. The routing index entry becomes {Method, Handler, Config}.
• A2A over gRPC lives in a companion package, livery_grpc_a2a, which composes this library with barrel_a2a. It stays out of this one so a gRPC user does not take on an A2A implementation, and out of barrel_a2a so an A2A user does not take on gpb and a code generation step. The config field above is what lets it hand its agent to the service handler from outside.

Changed

• The protobuf build uses gpb's use_packages, so a .proto can reference messages from another package (google.protobuf.Struct), with msg_fqname and service_fqname renamed back to their base names so generated Erlang names are unchanged.
• Bump livery to 0.9.2 and h2 to 0.12.x.

Full detail in CHANGELOG.md.