16: update changelog

Author: trash-and-fire

packages/lib/CHANGELOG.md

@@ -1,5 +1,15 @@
 # Lightweight Charts React Wrapper changelog
 
+## 2.1.0
+
+Added support for some new `lightweight-charts@4.1.0` features:
+- Implemented `<CustomSeries>` component.
+- Implemented `<SeriesPrimitive>` component.
+
+### Breaking changes
+
+- `lightweight-charts` package breaks type backward compatibility. Typescript users should be prepared to work with new types and update the Lightweight Chart package to at least version 4.1.0.
+
 ## 2.0.0
 
 In this major release, the required version of the Lightweight Charts package has been upgraded to 4.0.0 to support the package's new features.