Release v2.2.0

Update version to 2.2.0 and add changelog entries for:
- CMAB (Contextual Multi-Armed Bandit) support
- Multi-region data hosting support
- Enhanced decision notifications
- Public API additions and changes

Author: Mat001

CHANGELOG.MD

@@ -4,6 +4,32 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [2.2.0] - January 25, 2025
+
+### New Features
+- **CMAB (Contextual Multi-Armed Bandit) Support**: Added comprehensive support for CMAB experiments, enabling dynamic optimization based on user context and real-time learning
+- **Multi-Region Data Hosting Support**: Added SDK support for multi-region data hosting to improve performance and comply with data residency requirements
+
+### Public API Changes
+
+#### CMAB-Related Changes
+- **New CMAB Package** (`pkg/cmab`):
+  - `Service` interface for CMAB decision services
+  - `Client` interface for CMAB API clients  
+  - `Decision` struct for CMAB decision results
+  - `Config` struct for CMAB configuration options
+  - `NewDefaultConfig()` function for default CMAB configuration
+- **Client Factory**: `WithCmabConfig(*cmab.Config) OptionFunc` - New option for setting CMAB configuration
+- **Event Metadata**: `CmabUUID` field added to DecisionMetadata for CMAB tracking
+
+#### Multi-Region and Notification Changes
+- **Project Config Interface**: `GetRegion() string` method for multi-region support
+- **Event Structures**: `Region` field added to event structures
+- **Multi-Region Support**: `SupportedRegions` map exported in event package with region-based endpoint selection
+- **Enhanced Decision Notifications**: Decision notification listener payload now includes:
+  - `experimentId` field for experiment identification
+  - `variationId` field for variation identification
+
 ## [2.1.0] - November 8, 2024
 
 ### Enhancements

pkg/event/version.go

@@ -18,7 +18,7 @@
 package event
 
 // Version is the current version of the client
-var Version = "2.1.0"
+var Version = "2.2.0"
 
 // ClientName is the name of the client
 var ClientName = "go-sdk"