Add changelog entry for benchmarks link fix

Author: rohansood10

CHANGELOG.md

@@ -59,6 +59,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#4139](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4139))
 
 ### Fixed
+- Fix dead benchmarks link in documentation
+  ([#4238](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4238))
 - `opentelemetry-instrumentation-mysql`: Refactor MySQL integration test mocks to use concrete DBAPI connection attributes, reducing noisy attribute type warnings.
   ([#4116](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4116))
 - `opentelemetry-instrumentation-cassandra`: Use `_instruments_any` instead of `_instruments` for driver dependencies so that having either `cassandra-driver` or `scylla-driver` installed is sufficient