Update react native version in nativebase-template

Good day,

We tried creating a project with `npx react-native init MyApp --template @native-base/react-native-template` according to the instructions [here](https://docs.nativebase.io/install-rn). However, the RN version it comes with is outdated and we were not able to run it.

We had to create a blank RN project using `npx react-native init MyApp` and then adding nativebase manually.

Is it possible to update the template to use latest RN and other dependencies versions to ease the development process?

Thank you,