[DX-2403], major version bump

MIGRATION.md

@@ -1,3 +1,53 @@
+## Migrating from v3 to v4
+
+This document outlines the necessary change made to the `ISystemFields` interface.  
+The `publish_details` field is no longer an array of objects — it is now a single object.
+
+This update aligns the generated types with the actual Contentstack API response.
+
+
+
+## Before 
+
+```typescript
+export interface ISystemFields {
+  uid?: string;
+  created_at?: string;
+  updated_at?: string;
+  created_by?: string;
+  updated_by?: string;
+  _content_type_uid?: string;
+  tags?: string[];
+  ACL?: any[];
+  _version?: number;
+  _in_progress?: boolean;
+  locale?: string;
+  publish_details?: IPublishDetails[]; // Incorrect: Array of IPublishDetails
+  title?: string;
+}
+```
+
+
+## After 
+```typescript
+export interface ISystemFields {
+  uid?: string;
+  created_at?: string;
+  updated_at?: string;
+  created_by?: string;
+  updated_by?: string;
+  _content_type_uid?: string;
+  tags?: string[];
+  ACL?: any[];
+  _version?: number;
+  _in_progress?: boolean;
+  locale?: string;
+  publish_details?: IPublishDetails; // Corrected: Single IPublishDetails object
+  title?: string;
+}
+```
+---
+
 ## Migrating from v2 to v3
 This document outlines the necessary changes to separate nested modular blocks into distinct interfaces. This update will affect how modular blocks are structured and used throughout the codebase.