Updated changelog

Author: lohanidamodar

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## 7.0.0
-* **BREAKING** flutter_web_auth package now switched to 
+* **BREAKING** Switched to using [flutter_web_auth_2](https://pub.dev/packages/flutter_web_auth_2), check Getting Started section in Readme for changes (Android and Web will require adjustments for OAuth to work properly)
+* Fixes Concurrent modification issue
+* Upgrade dependencies
 
 ## 6.0.0
 * Support for Appwrite 0.15