chore(*): Update changelog.

Author: skrustev

CHANGELOG.md

@@ -2,6 +2,14 @@
 
 All notable changes for each version of this project will be documented in this file.
 
+## 18.1.0
+### New Features
+- `IgxPivotGrid`
+    - Added horizontal layout for row dimensions. Can be configured through the `pivotUI` `rowLayout` property.
+    - Added `horizontalSummary` property for each IPivotDimension, enabling summary row when using horizontal layout.
+    - Keyboard navigation now can move in to row headers back and forth from any row dimension headers or column headers.
+    - Added keyboard interactions for row dimension collapse using `Alt + Arrows` and row headers sorting using `Ctrl + Arrow Up/Down`.
+
 ## 18.0.0
 ### New Features
 - `IgxCombo`, `IgxSimpleCombo`: