Update README.md RxJava version

Author: WeRockStar

README.md

@@ -33,7 +33,7 @@ Users switching from 1.x to 2.x have to re-organize their imports, but carefully
 
 Add this in your build.gradle
 ```groovy
-compile 'io.reactivex.rxjava2:rxjava:2.0.6'
+compile 'io.reactivex.rxjava2:rxjava:2.1.1'
 ```
 If you are using RxAndroid also, then add the following
 ```groovy