title: I need to create react-native app with sdk 25 and gradle 2
body: <p>I've installed react-native-cli version 2.0.1 and yarn version 1.16.0, android studio, jdk version 8.
  when I create a project with android studio, everything is fine but when wanna create project with react native, it does not work.
  I checked the graddle of react-native project, it uses sdk 28, and gradle 5!! how can I set reac-native to create projects with sdk 25 and gradle 2 every time?</p>