Update README.md

Author: joncham

README.md

@@ -16,6 +16,10 @@ Branches for released Unity versions are of the form unity-\<version\>\[-mbe\][-
 * [unity-trunk (PR to this branch for Mono)](https://github.com/Unity-Technologies/mono/tree/unity-trunk)
 * [unity-master (PR to this branch for MonoBleedingEdge)](https://github.com/Unity-Technologies/mono/tree/unity-master)
 
+#### 2018.1
+* [unity-2018.1](https://github.com/Unity-Technologies/mono/tree/unity-2018.1)
+* [unity-2018.1-mbe](https://github.com/Unity-Technologies/mono/tree/unity-2018.1-mbe)
+
 #### 2017.3
 * [unity-2017.3](https://github.com/Unity-Technologies/mono/tree/unity-2017.3)
 * [unity-2017.3-mbe](https://github.com/Unity-Technologies/mono/tree/unity-2017.3-mbe)