Fix Usage on README (#89)

Apparently currently the option `--template` already adds the `react-native-template` to the path, and if we use what's on README we will have this path that doesn't exist:

https://registry.yarnpkg.com/react-native-template-react-native-template-typescript

Changing to just `--template typescript` fixes it.

Author: julioxavierr

README.md

@@ -28,13 +28,13 @@
 > `react-native@0.61.0` or higher
 
 ```sh
-npx react-native init MyApp --template react-native-template-typescript
+npx react-native init MyApp --template typescript
 ```
 
 > `react-native@0.60.x`
 
 ```sh
-npx react-native init MyApp --template react-native-template-typescript@6.2.0
+npx react-native init MyApp --template typescript@6.2.0
 ```
 
 ### Note on the legacy CLI