point docs to java-sdk

Author: realark

README.md

@@ -1,5 +1,7 @@
 # Braintrust Kotlin API Library
 
+NOTE: This repo is a kotlin client for the Braintrust REST api. If you wish to trace and write evals, see the [Braintrust Java SDK](https://github.com/braintrustdata/braintrust-sdk-java)
+
 The Braintrust Kotlin SDK provides convenient access to the Braintrust REST API from applications written in Kotlin. It includes helper classes with helpful types and documentation for every request and response property.
 
 The Braintrust Kotlin SDK is similar to the Braintrust Java SDK but with minor differences that make it more ergonomic for use in Kotlin, such as nullable values instead of `Optional`, `Sequence` instead of `Stream`, and suspend functions instead of `CompletableFuture`.