update CHANGELOG

CHANGELOG.md

@@ -1,5 +1,20 @@
 # Changelog     
 
+## milvus-sdk-java 0.2.1 (TBD)
+
+### Bug
+---
+
+### Improvement
+---
+- \#49 - Add waitTime option in ConnectParam
+
+### Feature
+---
+
+### Task
+---
+
 ## milvus-sdk-java 0.2.0 (2019-10-21)
 
 ### Bug