expires tag

[timkelty]

Description

Adds a expires tag for easier Twig access to \Craft::$app->getResponse()->setCacheHeaders.

// Cache-Control: public, max-age=1814400
{% expires in 3 weeks %}

// Cache-Control: public, max-age=30
{% expires on now|date_modify('+30 seconds') %}

// Cache-Control: no-cache, no-store, must-revalidate
{% expires %}

Based on 4.10 as it is useful for Cloud, but could be rebased to 5.x.

For no-cache, I went with just {% expires %} vs {% expires now %}, as it seemed like with now, we should support more relative times like tomorrow.