Change @react-native-community/netinfo version

With #248, the netinfo version has changed to 5.3.x.
Bumping up the version mentioned here to keep the readme upto date.

README.md

@@ -79,7 +79,7 @@ $ yarn add react-native-offline
 $ npm i --save react-native-offline
 ```
 
-This library uses `@react-native-community/netinfo@4.x.x` version underneath the hood. You then need to link the native parts of the library for the platforms you are using.
+This library uses `@react-native-community/netinfo@5.x.x` version underneath the hood. You then need to link the native parts of the library for the platforms you are using.
 
 If you are on React Native v0.60, you don't need to do anything else, since it supports autolinking. For iOS, just go to the `ios` folder and run `pod install`. However, autolinking might not pick up and install the `@react-native-community/netinfo` dependency. If that happens, first install `@react-native-community/netinfo` directly, then run `pod install`, then install `react-native-offline` and finish with `pod install`.