message: Ignore dirty grpc submodule
  When using CMake to build, the zlib submodule inside of the grpc
  submodule ends up with a generated file that makes Git consider the
  submodule dirty. This state can be ignored for day-to-day development.
diff: [submodule "thirdparty/grpc"]
  path = thirdparty/grpc
  url = https://github.com/grpc/grpc.git
  + # When using CMake to build, the zlib submodule inside of the grpc
  + # submodule ends up with a generated file that makes Git consider
  + # the submodule dirty.
  + ignore = dirty
  [submodule "thirdparty/rapidjson"]
  path = thirdparty/rapidjson
  