Update README.md

Author: jinzhongjia

README.md

@@ -13,4 +13,8 @@ This is an implementation of [MessagePack](https://msgpack.org/index.html) for [
 The current protocol implementation has been completed, but it has not been fully tested.
 Only limited unit testing has been conducted, which does not cover everything.
 
-now `msgpack-rpc` is under developing!
+now `msgpack-rpc` is under developing!
+
+## Related projects
+
+- [znvim](https://github.com/jinzhongjia/znvim)