feat(docs): Add section on updating DataHub for 1.1.0 (#13561)

Author: esteban

docs/how/updating-datahub.md

@@ -34,10 +34,11 @@ This file documents any backwards-incompatible changes in DataHub and assists pe
 
 ### Breaking Changes
 
+- #12795: slack source v2 - now ingests all user and channels. Make sure the ingestion source and GMS are on the same version of DataHub.
 - #13004: The `acryl-datahub-airflow-plugin` dropped support for Airflow 2.3 and 2.4.
 - #13186: NoCode Migration Removed - This code hasn't been required in many years. If needed, a user should upgrade to DataHub 1.0.x prior to upgrading to a later version.
 - #13397: `async_flag` removed from rest emitter, replaced with emit mode ASYNC
-- #13456: Remove the exposure of `CREATE_ER_MODEL_RELATIONSHIP_PRIVILEGE` due to unsupported / incomplete functionality causing confusion among admins of DataHub.
+- #13120: DataHub Actions Integration: Moved datahub-actions into OSS DataHub. Users building their own DataHub Actions docker images can now build from the OSS project.
 
 ### Known Issues
 
@@ -51,6 +52,15 @@ This file documents any backwards-incompatible changes in DataHub and assists pe
 
 ### Other Notable Changes
 
+- SDK Improvements: Added URN to URL helpers, lineage client, ML model support, and search enhancements.
+- Connector Improvements: Significant enhancements to PowerBI, Superset, MLflow, and Redshift connectors.
+- New Connectors: Added connectors for Hex notebooks and VertexAI.
+- Iceberg Connector Refactoring: The Iceberg connector has been completely refactored to use MCPWs instead of MCEs.
+- Entity Subtypes Model Change: The addition of subtypes to most entities.
+- #13151 #13255: UI Search Bar Redesign: search bar with new autocomplete functionality has been added.
+- #12976: Edit Lineage Feature: Added ability to edit lineage directly in the UI.
+- #12983 #13107: Manage Tags Interface: Added a dedicated "Manage Tags" navigation page.
+- #13361: Theme Support: Added foundation for basic theme support with primary color configuration.
 - #13165 - OpenAPI v3 Patching Improvements
 - #13397 - Ingestion Rest Emitter - Added EmitMode parameter for write guarantees.
   - SYNC_WAIT: Synchronously updates the primary storage (SQL) but asynchronously updates search storage (Elasticsearch). Provides a balance between consistency and performance. Suitable for updates that need to be immediately reflected in direct entity retrievals but where search index consistency can be slightly delayed.