update changelog

Author: A-Baji

CHANGELOG.md

@@ -9,6 +9,10 @@ Observes [Semantic Versioning](https://semver.org/spec/v2.0.0.html) standard and
 - An openAI image generation command
 - The gpt3.5 model to the openai command and made it the default
 - A chatGPT command with chat history functionality
+- Custom emoji support for custom models.
+
+### Fixed
+- Upgrading the packaged executable version now properly applies any new features to existing, non-custom cogs
 
 ### Changed