Upgrade govuk_template to version 0.19.2
Upgrade govuk_template to version 0.19.2

Fixes the following:

- Increase skiplink colour contrast
https://github.com/alphagov/govuk_template/pull/263

- Fix Scala compile issues for Play template
https://github.com/alphagov/govuk_template/pull/261

guidance-guarantee-programme/pension_guidance,guidance-guarantee-programme/pension_guidance,guidance-guarantee-programme/pension_guidance