Correct date to be that the code was published
Correct date to be that the code was published

As described in
https://github.com/alphagov/govuk_frontend_toolkit/pull/156#discussion_r24578831

quis/govuk_frontend_toolkit,quis/govuk_frontend_toolkit,TFOH/govuk_frontend_toolkit,alphagov/govuk_frontend_toolkit,TFOH/govuk_frontend_toolkit,alphagov/govuk_frontend_toolkit,TFOH/govuk_frontend_toolkit,alphagov/govuk_frontend_toolkit,alphagov/govuk_frontend_toolkit,quis/govuk_frontend_toolkit,quis/govuk_frontend_toolkit,TFOH/govuk_frontend_toolkit