Add Nginx proxy entry for docs.content-api.publishing...
Add Nginx proxy entry for docs.content-api.publishing...

This will be hosted by GitHub Pages, the DNS entry will come
later.

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet