Update to 1.4.0

https://github.com/alphagov/govuk_frontend_toolkit/compare/ba9e40af66be497abc9c1d24156c8dc6d6c64db4...e295f45f59495f8e37e37a105da6d9d8b2695a54

- New phase banner styles
- Removed trailing commas
- Redrawn important icon