Update service-workers.md
Update service-workers.md

After proofreading.
DivanteLtd/vue-storefront,pkarw/vue-storefront,pkarw/vue-storefront,DivanteLtd/vue-storefront,DivanteLtd/vue-storefront,pkarw/vue-storefront,DivanteLtd/vue-storefront,pkarw/vue-storefront