Allow time format to be mutable (set in place) [skip ci]
Allow time format to be mutable (set in place) [skip ci]

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