Update nginx Pin Version
Update nginx Pin Version

relates to https://github.com/alphagov/govuk-puppet/pull/4990

Wrong package version is causing puppet run warnings.
`aptitude show nginx` displays the correct package version.

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