Fix the release name for grafana
Fix the release name for grafana

According to the puppet apt module docs:
release: Specifies a distribution of the Apt repository.
repos: Specifies a component of the Apt repository. Valid options: a string. Default: 'main'.

So release should be 'jessie'

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