update changelog

Author: nozik

Diff for: CHANGELOG.md

@@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - `opentelemetry-instrumentation-aws-lambda` Adds support for configurable flush timeout  via `OTEL_INSTRUMENTATION_AWS_LAMBDA_FLUSH_TIMEOUT` property. ([#825](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/825))
+- `opentelemetry-instrumentation-pika` Adds support for versions between `0.12.0` to `1.0.0`. ([#837](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/837))
 
 ### Fixed