Update eslint-config-react-app peerDeps

Created by: alexkrolick

Some of the peer dependencies for the ESLint config are lagging a major version. It would be nice to update the config to match.

• jsx-a11y changelog Deprecations & new features
• babel-eslint changelog no major changes except updating to Babel 7 (this might be a big deal, I am not sure)

This would be a good first issue for someone 😄