Update changelog

Author: alexrudall

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add missing parameters (order, limit, etc) to Runs, RunSteps and Messages - thanks to [@shalecraig](https://github.com/shalecraig) and [@coezbek](https://github.com/coezbek)
 - Add missing Messages#list spec - thanks [@adammeghji](https://github.com/adammeghji)
 - Add Messages#modify to README - thanks to [@nas887](https://github.com/nas887)
+- Don't add the api_version (`/v1/`) to base_uris that already include it - thanks to [@kaiwren](https://github.com/kaiwren) for raising this issue
 
 ### Security