Update CHANGELOG.md

Author: isc-tleavitt

CHANGELOG.md

@@ -6,7 +6,7 @@ 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] - Unreleased
+## [3.1.1] - 2024-07-31
 
 ### Fixed
 - #39: Fixed bug where results viewer gave divide by zero error when there were 0 executed methods in the covered code