refactor(headers): Use header!() macro for Upgrade header field
refactor(headers): Use header!() macro for Upgrade header field

ianks/hyper,mlalic/hyper,fengsp/hyper,achanda/hyper,nstoddard/hyper,bheesham/hyper,mlalic/hyper,nickgonzales/hyper,tshepang/hyper,clatour/hyper,Twey/hyper,reem/hyper,golddranks/hyper,hyperium/hyper,mneumann/hyper,giftcards/hyper,pyfisch/hyper,manuel-woelker/hyper,markuskobler/hyper,yangxingpping/hyper,nstoddard/hyper,Keats/hyper,mre/hyper,erickt/hyper,hannobraun/hyper,peterhj/hyper,tshepang/hyper,bonifaido/hyper,tempbottle/hyper,mitsuhiko/hyper,jmmaranan/hyper,lame-nickname/hyper,golddranks/hyper,steveklabnik/hyper,mfeckie/hyper,youprofit/hyper,markuskobler/hyper,yazaddaruvala/hyper,nickgonzales/hyper,sfackler/hyper,hannobraun/hyper,Twey/hyper,tshepang/hyper,nickgonzales/hyper,hyperium/hyper,fhahn/hyper,Twey/hyper,TimNN/hyper,yazaddaruvala/hyper,mikedilger/hyper,Keats/hyper,golddranks/hyper,hannobraun/hyper,markuskobler/hyper,rschulman/hyper,hyperium/hyper,fuchsnj/hyper,huonw/hyper,softprops/hyper,Keats/hyper