change from valid-package-names to allowed-package-names and document
change from valid-package-names to allowed-package-names and document

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