Add rubygem-google-protobuf 3.2.0.2

rubygem-google-protobuf is a Ruby extension that implements Protocol Buffers
functionality. It makes use of generated Ruby code that defines message and enum
types in a Ruby DSL. You may write definitions in this DSL directly, but we
recommend using protoc's Ruby generation support with .proto files. The build
process in this directory only installs the extension; you need to install
protoc as well to have Ruby code generation functionality.

WWW: https://developers.google.com/protocol-buffers/
WWW: https://github.com/google/protobuf/tree/master/ruby