chore(changelog): Update changelog with primaryKey exposed argument (#12755)

* chore(changelog): Update changelog with primaryKey exposed argument

* chore(*): update primaryKey changelog content

* chore(*): fix content typo

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Co-authored-by: Konstantin Dinev <[email protected]>

Author: dobromirts

CHANGELOG.md

@@ -7,6 +7,7 @@ All notable changes for each version of this project will be documented in this
 ### New Features
 - `IgxGrid`, `IgxTreeGrid`, `IgxHierarchicalGrid`:
     - `GroupMemberCountSortingStrategy` is added, which can be used to sort the grid by number of items in each group in ASC or DESC order, if grouping is applied.
+    - A new argument `primaryKey` has been introduced to `IRowDataEventArgs` Interface and part of the event arguments that are emitted by the `rowAdded` and `rowDeleted` events. When the grid has a primary key attribute added, then the emitted `primaryKey` event argument represents the row ID, otherwise it defaults to undefined.
 - `IgxColumnComponent`
     - Added `currRec` and `groupRec` parameters to the `groupingComparer` function that give access to the all properties of the compared records.