update changelog

Author: stevehu

CHANGELOG.md

@@ -14,7 +14,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ### Changed
 - Fixes #20 added default messages to empty messages on ValidatorTypeCode. Thanks @eskabetxe
-- Fixes #21 only check subschema if distinct from schema, and minor changes. Thanks @eskabetxe
+- Fixes #22 only check subschema if distinct from schema, and minor changes. Thanks @eskabetxe
 - Fixes #24 update dependencies versions. Thanks @eskabetxe
 
 ## 0.1.5 - 2017-03-25