chore(modals): update container dependencies

[hzhu]

Description

This pull request updates the react-modal container dependencies so that modals can take advantage of the new restore focus feature which was added to container-focusjail.

Demo

The demo can be found here: https://modals-dep-update.netlify.com/modals/#examples. The keyboard focus is now restored upon closing the modal for three scenarios:

1. When a user selects the "X" close button in the top corner of the modal.
2. When a user presses the "Escape" key.
3. When a user clicks the backdrop.

Checklist

• 🌐 Styleguidist demo is up-to-date (yarn start)
• ⬅️ renders as expected with reversed (RTL) direction
• ♿ analyzed via axe and evaluated using VoiceOver
• 📝 tested in Chrome, Firefox, Safari, Edge, and IE11

[coveralls]

Coverage remained the same at 93.977% when pulling 2ad4705 on hzhu/update-modal-container-dep into 03122a3 on master.