Upgrade Go version to 1.15.8 on Jenkins and CI Agent instances
Upgrade Go version to 1.15.8 on Jenkins and CI Agent instances

Jenkins (Deploy & CI) run builds and tests for Router using Golang.

This removes some unused versions of Go - 1.11.13 and 1.15.8 should be
the only versions in use by Router.

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