Update CHANGELOG.md

Note 3.1.1 isn't released yet

Author: isc-tleavitt

CHANGELOG.md

@@ -5,7 +5,7 @@ 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).
 
-## [3.1.1] - 2024-07-12 
+## [3.1.1] - Unreleased
 
 ### Fixed
 - #39: Fixed bug where results viewer gave divide by zero error when there were 0 executed methods in the covered code 
@@ -30,4 +30,4 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - #25: Fix so the tool works on 2023.1
 
 ## [2.1.3] - 2022-03-30
-- Last released version before CHANGELOG existed.
+- Last released version before CHANGELOG existed.