update readme

Author: xwenliang

README.md

@@ -8,7 +8,7 @@ A Picker written in pure javascript for cross-platform support.
 It was most likely an example of how to build a cross-platform Picker Component use [react-native-picker-android](https://github.com/beefe/react-native-picker-android).
 
 ###Warn
-if 0.14.2 <= react-native <=0.24 `npm install [email protected] --save`
+if 0.14.2 <= react-native <=0.24 `npm install [email protected] --save`  
 if 0.24 < react-native `npm install react-native-picker --save`
 
 ####Demo