Migrate project from rnpm to react-native.config.js

[ja-bravo]

Summary

Due to an update to the RN CLI we need to migrate from rnpm to react-native.config.js.
It gets rid of the following warning

warn The following packages use deprecated "rnpm" config that will stop working from next release:
  - react-native-google-signin: https://github.com/react-native-community/react-native-google-signin
Please notify their maintainers about it. You can find more details at https://github.com/react-native-community/cli/blob/master/docs/configuration.md#migration-guide.

[ShaMan123]

+1

[ShaMan123]

shouldn't this be dependency instead of project?

[1602]

module.exports = {
    dependency: {
        platforms: {
            ios: {
                project: 'ios/RNGoogleSignin.xcodeproj'
            }
        }
    }
};

[vonovak]

First, let me just say that the config option has been there for a long time and I'm not even sure if it needs to be there. Can someone verify if we need to include config for rn-cli?