Replace 2.0.0-rc.0 by next tag

README.md

 ## Setup
 
 ```bash
-$ npm install --save react-native-permissions@2.0.0-rc.0
+$ npm install --save react-native-permissions@next
 # --- or ---
-$ yarn add react-native-permissions@2.0.0-rc.0
+$ yarn add react-native-permissions@next
 ```
 
 ### iOS