Update CHANGELOG for 0.2.0 release

Former-commit-id: db4bf76619bdef8928fe2d7705aecf695d979d3c

cpp/CHANGELOG.md

@@ -2,30 +2,43 @@
 
 Please mark all change in change log and use the ticket from JIRA.
 
-## [Unreleased]
+# MegaSearch 0.3.0 (TBD)
 
-### Bug
+## Bug
 
-### Improvement
+## Improvement
 
-### New Feature
+## New Feature
+
+## Task
+
+# MegaSearch 0.2.0 (2019-05-31)
+
+## Bug
+
+- MS-32 - Fix thrift error
+- MS-34 - Fix prometheus-cpp thirdparty
+
+## Improvement
+
+- MS-20 - Clean Code Part 1
+
+## New Feature
 
 - MS-5 - Implement Auto Archive Feature
-- MS-16 - Implement metrics without prometheus
 - MS-6 - Implement SDK interface part 1
+- MS-16 - Implement metrics without prometheus
 - MS-21 - Implement SDK interface part 2
 - MS-26 - cmake. Add thirdparty packages
 - MS-31 - cmake: add prometheus
 - MS-33 - cmake: add -j4 to make third party packages build faster
 - MS-27 - support gpu config and disable license build config in cmake
 - MS-47 - Add query vps metrics
+- MS-37 - Add query, cache usage, disk write speed and file data size metrics
+- MS-30 - Use faiss v1.5.2
 
-### Task
+## Task
 
 - MS-1 - Add CHANGELOG.md
 - MS-4 - Refactor the vecwise_engine code structure
-- MS-20 - Clean Code Part 1
-- MS-30 - Use faiss v1.5.2
-- MS-32 - Fix thrift error
-- MS-34 - Fix prometheus-cpp thirdparty
-- MS-37 - Add query, cache usage, disk write speed and file data size metrics
+