Don't use GA, use firebase (#287)

Remove GA from the list of react device-mode sdks. Google forced folks to move mobile implementations to Firebase.

Author: sanscontext

README.md

@@ -177,7 +177,6 @@ In Xcode:
 | [Facebook App Events](https://www.npmjs.com/package/@segment/analytics-react-native-facebook-app-events-ios) | :white_check_mark: | :x:                | `@segment/analytics-react-native-facebook-app-events-ios` |
 | [Firebase](https://www.npmjs.com/package/@segment/analytics-react-native-firebase)                           | :white_check_mark: | :white_check_mark: | `@segment/analytics-react-native-firebase`                |
 | [Flurry](https://www.npmjs.com/package/@segment/analytics-react-native-flurry)                               | :white_check_mark: | :white_check_mark: | `@segment/analytics-react-native-flurry`                  |
-| [Google Analytics](https://www.npmjs.com/package/@segment/analytics-react-native-google-analytics)           | :white_check_mark: | :white_check_mark: | `@segment/analytics-react-native-google-analytics`        |
 | [Intercom](https://www.npmjs.com/package/@segment/analytics-react-native-intercom)                           | :white_check_mark: | :white_check_mark: | `@segment/analytics-react-native-intercom`                |
 | [Localytics](https://www.npmjs.com/package/@segment/analytics-react-native-localytics)                       | :white_check_mark: | :white_check_mark: | `@segment/analytics-react-native-localytics`              |
 | [Mixpanel](https://www.npmjs.com/package/@segment/analytics-react-native-mixpanel)                           | :white_check_mark: | :white_check_mark: | `@segment/analytics-react-native-mixpanel`                |