[Docs] Update changelog

Author: lindyhopchris

CHANGELOG.md

@@ -3,6 +3,18 @@
 All notable changes to this project will be documented in this file. This project adheres to
 [Semantic Versioning](http://semver.org/) and [this changelog format](http://keepachangelog.com/).
 
+## Unreleased (2.0)
+
+### Added
+
+- Package now supports PHP 8.1.
+
+### Changed
+
+- Upgraded the `laravel-json-api/neomerx-json-api` dependency to `5.0`.
+- Upgraded the `laravel-json-api/core` dependency to `2.0`.
+- Added return types to internal methods to remove deprecation messages in PHP 8.1
+
 ## [1.1.0] - 2022-01-03
 
 ### Fixed