[#70264760] Bump govuk_mirrorer version to 1.3.0
[#70264760] Bump govuk_mirrorer version to 1.3.0

This picks up the instrumentation for various parts of the mirrorer
that have been added recently.

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