Update Changelog for release of version 5.5.1

Author: LaunchDarklyCI

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 All notable changes to the LaunchDarkly Ruby SDK will be documented in this file. This project adheres to [Semantic Versioning](http://semver.org).
 
+## [5.5.1] - 2019-01-17
+### Fixed:
+- Fixed several documentation comments that had the wrong parameter names. There are no other changes in this release; it's only to correct the documentation.
+
 ## [5.5.0] - 2019-01-17
 ### Added:
 - It is now possible to use Consul or DynamoDB as a persistent feature store, similar to the existing Redis integration. See the `LaunchDarkly::Integrations::Consul` and `LaunchDarkly::Integrations::DynamoDB` modules, and the reference guide [Using a persistent feature store](https://docs.launchdarkly.com/v2.0/docs/using-a-persistent-feature-store).