CHANGELOG.md in rubocop-rake-0.3.1 vs CHANGELOG.md in rubocop-rake-0.4.0

@@ -1,23 +1,29 @@
 # Change log
 
 ## master (unreleased)
 
-## 0.3.1 (2019-10-06)
-
-### Bug fixes
-
-* [#17](https://github.com/rubocop-hq/rubocop-rake/pull/17): Filter target files for Rake/ClassDefinitionInTask cop. ([@pocke][])
-
 <!--
 
 ### New features
 
 ### Bug fixes
 
 ### Changes
 
 -->
+
+## 0.4.0 (2019-10-13)
+
+### New features
+
+* [#13](https://github.com/rubocop-hq/rubocop-rake/issues/13): Add Rake/DuplicateTask cop. ([@pocke][])
+
+## 0.3.1 (2019-10-06)
+
+### Bug fixes
+
+* [#17](https://github.com/rubocop-hq/rubocop-rake/pull/17): Filter target files for Rake/ClassDefinitionInTask cop. ([@pocke][])
 
 ## 0.3.0 (2019-09-25)
 
 ### New features