Updated changelog

CHANGELOG.md

@@ -5,6 +5,15 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.0.0]
+
+- Fully implemented version 0.5.2 of the GrowthBook SDK spec.
+- Added support for retrieving features (both regular and encrypted) from the GrowthBook API with in-memory caching.
+- Added support for retrieving features (both regular and encrypted) in near-realtime with Server Sent Events (when preferred and available).
+- Added extensive support for logging.
+- Added more robust error handling.
+- New unit test structure for easier use of the standard cases.json test suite.
+
 ## [0.2.0]
 
 - Corrected name of `IGrowthbook` to `IGrowthBook`