docs: Update changelog

Author: Stranger6667

CHANGELOG.md

@@ -2,10 +2,18 @@
 
 ## [Unreleased]
 
+### Changed
+
+- Improved error messages. [#27](https://github.com/Stranger6667/css-inline/issues/27)
+
 ### Fixed
 
 - Ignore `@media` queries, since they can not be inlined. [#7](https://github.com/Stranger6667/css-inline/issues/7)
 
+### Performance
+
+- Improve performance for merging new styles in existing "style" attributes.
+
 ## 0.1.0 - 2020-06-22
 
 - Initial public release