Update changelog for v2.3.1

docs/changelog/README.md

@@ -9,8 +9,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
+
+
+## [v2.3.1]
 ### Changed
 - Only set attributes if they're not null or undefined.
+- Remove duplicate names from `attributesForObject` and `attributesForInstance`.
 
 
 ## [v2.3.0]
@@ -210,7 +214,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Barebones release of Fixture Riveter: fixtures, traits, associations
 - Barebones tutorial
 
-[Unreleased]: https://github.com/Batteri/fixture-riveter/compare/v2.3.0...HEAD
+[Unreleased]: https://github.com/Batteri/fixture-riveter/compare/v2.3.1...HEAD
+[v2.3.1]: https://github.com/Batterii/fixture-riveter/releases/tag/v2.3.1
 [v2.3.0]: https://github.com/Batterii/fixture-riveter/releases/tag/v2.3.0
 [v2.2.0]: https://github.com/Batterii/fixture-riveter/releases/tag/v2.2.0
 [v2.1.0]: https://github.com/Batterii/fixture-riveter/releases/tag/v2.1.0