Merge pull request #1336 from Unity-Technologies/readme

Branch for 2020.2 updates

Author: ashwinimurt

README.md

@@ -17,6 +17,9 @@ Branches for released Unity versions are of the form unity-\<version\>\[-mbe\][-
 #### Trunk
 * [unity-master (PR to this branch for MonoBleedingEdge)](https://github.com/Unity-Technologies/mono/tree/unity-master)
 
+#### 2020.2
+* [unity-2020.2-mbe](https://github.com/Unity-Technologies/mono/tree/unity-2020.2-mbe)
+
 #### 2020.1
 * [unity-2020.1-mbe](https://github.com/Unity-Technologies/mono/tree/unity-2020.1-mbe)