Update package.json for govuk-elements-sass
Update package.json for govuk-elements-sass

- Add a description
- Update the version number to the current version of govuk elements
- Add the repository field
- Move the govuk frontend toolkit to dependencies

joelanman/govuk_elements,gavboulton/govuk_elements,gavboulton/govuk_elements,alphagov/govuk_elements,joelanman/govuk_elements,gavboulton/govuk_elements,alphagov/govuk_elements,alphagov/govuk_elements,alphagov/govuk_elements,gavboulton/govuk_elements