Update tsconfig.json

[leotm]

Summary

To give the community a better first-time experience getting up and running.

We should either leave noEmit on like in create-react-app (i.e. Revert #100), or can amend this PR to only incremental left on, but with the outDir as e.g. "./lib", add this to the exclude list (since the compiler doesn't exclude it by default unless you include e.g. ./src) then finally add our /lib to .gitignore.

Test Plan

What's required for testing (prerequisites)?

• npx --ignore-existing react-native init MyApp --template react-native-template-typescript
• cd MyApp

What are the steps to reproduce (after prerequisites)?

• yarn tsc

Compatibility

OS	Implemented
iOS	✅❌
Android	✅❌

Checklist

• I have tested this on a device and a simulator
• I added the documentation in README.md
• I mentioned this change in CHANGELOG.md
• I updated the typed files (TS and Flow)
• I added a sample use of the API in the example project (example/App.js)