Update CHANGELOG

Author: kraanzu

CHANGELOG.md

@@ -5,6 +5,10 @@ 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/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+### 3.1.8
+
+- Fix inaccurate accuracy calculation after the incorrect letters were fixed (#99)
+
 ### 3.1.7
 
 This release does not change any functionalities, just bumps the underlying tui and fixes upstream nixpkgs