Bump to 6.0.0rc1
Bump to 6.0.0rc1

kkopachev/thumbor,BetterCollective/thumbor,kkopachev/thumbor,scorphus/thumbor,davduran/thumbor,abaldwin1/thumbor,gi11es/thumbor,davduran/thumbor,scorphus/thumbor,Bladrak/thumbor,scorphus/thumbor,voxmedia/thumbor,marcelometal/thumbor,davduran/thumbor,thumbor/thumbor,scorphus/thumbor,voxmedia/thumbor,okor/thumbor,BetterCollective/thumbor,davduran/thumbor,abaldwin1/thumbor,fanhero/thumbor,gi11es/thumbor,abaldwin1/thumbor,abaldwin1/thumbor,Bladrak/thumbor,kkopachev/thumbor,BetterCollective/thumbor,fanhero/thumbor,okor/thumbor,fanhero/thumbor,okor/thumbor,marcelometal/thumbor,kkopachev/thumbor,thumbor/thumbor,thumbor/thumbor,fanhero/thumbor,marcelometal/thumbor,gi11es/thumbor,voxmedia/thumbor,thumbor/thumbor