Add lodash to CRA example

[AndrewMusgrave]

WHY are these changes introduced?

We shouldn't import packages that aren't dependencies. Lodash isn't a dep. https://github.com/Shopify/polaris-react/blob/master/examples/create-react-app/package.json

Part of #991

WHAT is this pull request doing?

Adding lodash

TODO:

• add changelog

How to 🎩

Run the example 👍

🎩 checklist

• Tested on mobile
• Tested on multiple browsers
• Tested for accessibility

[BPScott]

I'm not too familar with how mergeAppProviderOptions() and legacy context stuff does its thing, but do we need a deep merge there or could we get away with a shallow one using Object.assign()? If we can do that we wouldn't need this dependency.

EDIT: answered in another PR: we do need a deep merge for this

[elileto]

🚢 🚢 🚢 🚢 🚢 🚢 🚢 🚢 🚢

[solonaarmstrong-zz]

shrink ray needs a rerun here too