RCTAppState getCurrentappState:error - unknown argument 'attribute'

I did a fresh checkout of master, currently at `ff48e47`. Ran `yarn` to install node modules. Had to apply fix for XCode 11 ( `simulator.isAvailable !== true` in `findMatchingSimulator.js`. Ok, so far, not project related.

Now I am getting

>"Unknown argument type 'attribute' in method -[RCTAppState getCurrentappState:error:].
>Extend RCTConvert to support this type

I updated react-native from 0.58.5 to to 0.59.8, as suggested here:
[https://github.com/facebook/react-native/issues/25138](https://github.com/facebook/react-native/issues/25138).

Still, the same error. This is too much work, just for checking out how things are being done in NativeBase. Giving up here.

Please keep up the good work, I fully understand that it is time consuming to maintain this sample app.