Add changelog entry for new biweight axis keyword
Add changelog entry for new biweight axis keyword

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