Add changelog

Author: DylanRussell

CHANGELOG.md

@@ -17,6 +17,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - `opentelemetry-resource-detector-containerid`: make it more quiet on platforms without cgroups
   ([#3579](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3579))
+- `opentelemetry-instrumentation-vertexai`: migrate off the deprecated events API to use the logs API
+  ([#3625](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3626))
 
 ### Added