docs: add redis-valkey-base package entry to CHANGELOG

Author: sightseeker

CHANGELOG.md

@@ -15,6 +15,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - `opentelemetry-instrumentation-valkey` Instrumentation for Valkey
   ([#3478](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3478))
+- `opentelemetry-instrumentation-redis-valkey-base` Shared base package for Redis and Valkey instrumentation,
+  extracting common tracing logic into a reusable module
+  ([#3478](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3478))
 - `opentelemetry-instrumentation-confluent-kafka`: Loosen confluent-kafka upper bound to <3.0.0
   ([#4289](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4289))