Update changelog for v1.8.3

Author: jdalton

CHANGELOG.md

@@ -4,6 +4,14 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
+## [1.8.3](https://github.com/SocketDev/socket-sdk-js/releases/tag/v1.8.3) - 2025-09-30
+
+### Changed
+- Synced with OpenAPI definition
+- Improved TypeScript configuration for test type checking
+- Enhanced test infrastructure with vitest setup improvements
+- Removed duplicate test files for better maintainability
+
 ## [1.8.2](https://github.com/SocketDev/socket-sdk-js/releases/tag/v1.8.2) - 2025-09-29
 
 ### Fixed