Propose kotlinx.serialization as 3rd party lib
Has support for protobuf v2.
diff --git a/docs/third_party.md b/docs/third_party.md
index 3f73d89..0963fe2 100644
--- a/docs/third_party.md
+++ b/docs/third_party.md
@@ -58,6 +58,7 @@
* Javascript: http://code.google.com/p/protobuf-for-node/
* Javascript: http://code.google.com/p/protostuff/
* Julia: https://github.com/tanmaykm/ProtoBuf.jl
+* Kotlin: https://github.com/Kotlin/kotlinx.serialization
* Lua: http://code.google.com/p/protoc-gen-lua/
* Lua: http://github.com/indygreg/lua-protobuf
* Lua: https://github.com/Neopallium/lua-pb
