update CHANGELOG.md

Author: herin049

CHANGELOG.md

@@ -116,6 +116,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#3681](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3681))
 - `opentelemetry-instrumentation-flask`: Fix exemplars generation for `http.server.request.duration` and `http.server.duration` metrics
   ([#3912](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3912))
+- `opentelemetry-instrumentation-cassandra`: Replace SpanAttributes with semconv constants for DB attributes
+  ([#4055](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4055))
 
 ### Added