Fix changelog

Author: rocktavious

CHANGELOG.md

@@ -1,5 +1,5 @@
 ## [v2.0.0](https://github.com/rocktavious/mixpanel-unity/releases/tag/v2.0.0)
-### April 12th - 2018
+### September 24th - 2019
 
 #### This version is a complete rewrite of the library to support ALL platforms that unity can compile to.
 
@@ -9,6 +9,8 @@ The API has stayed compliant with the documentation though there maybe a few cha
 
 The github repo has also been structured so that it supports the Unity 2018.4 package manager (please see the README for package manager install instructions)
 
+This version of the library should support backwards compatibility with Unity 2018.x but it has only been tested with the 2018 LTS release.
+
 ---
 
 ## [v1.1.1](https://github.com/mixpanel/mixpanel-unity/releases/tag/v1.1.1)