Bust the service worker cache on every build
Bust the service worker cache on every build

Builds result in new fingerprinted assets and a new index.html file so
we need to bust the service worker cache anytime this happens.

jrjohnson/frontend,dartajax/frontend,djvoa12/frontend,dartajax/frontend,djvoa12/frontend,jrjohnson/frontend,ilios/frontend,ilios/frontend,thecoolestguy/frontend,thecoolestguy/frontend