Added release notes for 0.2.1.

Author: gastonortiz

README.md

@@ -1,5 +1,5 @@
 # Java Client Library (beta)
-### v0.2.0
+### v0.2.1
 
 ## Introduction
 Welcome my friends! This is the Poly API Java client GitHub page. If you are here, then it means you're familiar with what we do at Poly. If you aren't, you can always check [here](https://github.com/polyapi/poly-alpha).
@@ -301,6 +301,8 @@ Comparing to its Typescript counterpart, the Java library is still missing the f
 These features will be added in the future releases.
 
 ## Changelog
+### v0.2.1
+- Fixed bug in add-server-function that uploaded arguments without keys.
 ### v0.2.0
 - Improved type generation.
 - Unified the client usage.