Install the libpq-dev package on the new extracted publishing_api nodes
Install the libpq-dev package on the new extracted publishing_api nodes

Publishing_api has always has these installed implicitly, we're adding them
as an explicit requirement now the application lives on its own.

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