You can set the "main" in package.json to any file within your
project. If you do this, then you need to use registerRootComponent;
export default will not make this component the root for the Expo app
if you are using a custom entry file.
For example, let's say you want to make "src/main.js" the entry file
project root, for example. First, set this in package.json:
Then in "src/main.js", make sure you call registerRootComponent and
pass in the component you want to render at the root of the app.