Update CHANGELOG.md

Author: fredzqm

packages/database/CHANGELOG.md

@@ -1,6 +1,7 @@
 # Unreleased
 - [feature] Added ServerValue.increment() to support atomic field value increments
   without transactions.
+- [bug] Fixed Realtime Database URL parsing bug to support domains with more than 3 components.
 
 # Released
 - [fixed] Fixed an issue that caused large numeric values with leading zeros to