Added six to requirements
Added six to requirements

stargaser/astropy,StuartLittlefair/astropy,aleksandr-bakanov/astropy,AustereCuriosity/astropy,dhomeier/astropy,mhvk/astropy,joergdietrich/astropy,AustereCuriosity/astropy,funbaker/astropy,tbabej/astropy,larrybradley/astropy,tbabej/astropy,stargaser/astropy,mhvk/astropy,pllim/astropy,dhomeier/astropy,aleksandr-bakanov/astropy,bsipocz/astropy,joergdietrich/astropy,dhomeier/astropy,aleksandr-bakanov/astropy,lpsinger/astropy,DougBurke/astropy,mhvk/astropy,tbabej/astropy,saimn/astropy,AustereCuriosity/astropy,DougBurke/astropy,StuartLittlefair/astropy,StuartLittlefair/astropy,MSeifert04/astropy,astropy/astropy,larrybradley/astropy,bsipocz/astropy,stargaser/astropy,larrybradley/astropy,astropy/astropy,funbaker/astropy,larrybradley/astropy,AustereCuriosity/astropy,joergdietrich/astropy,DougBurke/astropy,saimn/astropy,bsipocz/astropy,pllim/astropy,dhomeier/astropy,mhvk/astropy,tbabej/astropy,pllim/astropy,mhvk/astropy,bsipocz/astropy,dhomeier/astropy,lpsinger/astropy,MSeifert04/astropy,larrybradley/astropy,saimn/astropy,MSeifert04/astropy,funbaker/astropy,DougBurke/astropy,StuartLittlefair/astropy,lpsinger/astropy,lpsinger/astropy,lpsinger/astropy,stargaser/astropy,kelle/astropy,pllim/astropy,StuartLittlefair/astropy,tbabej/astropy,astropy/astropy,kelle/astropy,kelle/astropy,saimn/astropy,AustereCuriosity/astropy,aleksandr-bakanov/astropy,joergdietrich/astropy,saimn/astropy,pllim/astropy,astropy/astropy,MSeifert04/astropy,funbaker/astropy,joergdietrich/astropy,kelle/astropy,astropy/astropy,kelle/astropy