Bump node-sass to 3.1.0 and grunt-sass to 1.0.0
Bump node-sass to 3.1.0 and grunt-sass to 1.0.0

Update both node-sass and grunt-sass to the latest versions.

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