Update README.md (#192)

Author: kelset

README.md

@@ -68,7 +68,7 @@ If you are part of a new startup  (<$5M raised, <2 years since founding),
 
 ```bash
 $ yarn add @segment/analytics-react-native
-$ yarn react-native link
+$ cd ios && pod install && cd .. # CocoaPods on iOS needs this extra step
 ```
 
 ## Usage