updated font-average to use github url
updated font-average to use github url

mtakayuki/homebrew-fonts,RJHsiao/homebrew-fonts,mtakayuki/homebrew-fonts,RJHsiao/homebrew-fonts,alerque/homebrew-fonts,unasuke/homebrew-fonts,caskroom/homebrew-fonts,caskroom/homebrew-fonts,victorpopkov/homebrew-fonts,victorpopkov/homebrew-fonts,guerrero/homebrew-fonts,guerrero/homebrew-fonts,alerque/homebrew-fonts