Update README.md

Author: TwoTenPvP

README.md

@@ -9,6 +9,7 @@ There is also a autogenerated Sandcastle [API reference](https://twotenpvp.githu
 
 ### Requirements
 * Unity 2017 or newer
+* .NET 4.6 or .NET 3.5 with .NET 2.0 non subset [Issue](https://github.com/TwoTenPvP/MLAPI/issues/43)
 
 ## Feature highlights
 * Host support (Client hosts the server)