feat(amp-pwa-lab): precache icons
feat(amp-pwa-lab): precache icons

Added the icons to the glob patterns in solution/workbox-cli-config.js

Change-Id: Id4adb6cc2148fe5e88f4985f94fc9fb1fb999b01

googlecodelabs/amp-pwa-workbox,googlecodelabs/workbox-lab,googlecodelabs/amp-pwa-workbox,googlecodelabs/workbox-indexeddb,googlecodelabs/workbox-lab,googlecodelabs/workbox-indexeddb