Updated Readme

Author: maximkhatskevich

README.md

@@ -47,4 +47,9 @@ With optional assign operator you do the same with just this:
 title ?= newTitleValue
 ```
 
-See unit tests for more examples.
+See unit tests for more examples.
+
+Swift 3
+=
+
+Starting from [version 2.0](https://github.com/maximkhatskevich/MKHOptionalAssign/releases/tag/2.0.0), this library supports Swift 3. For compatibility with Swift 2.2 and Swift 2.3 use [older version](https://github.com/maximkhatskevich/MKHOptionalAssign/releases/tag/1.0.0).