Add v2.0.12 and v3.1.2 to the changelog [skip ci]
Add v2.0.12 and v3.1.2 to the changelog [skip ci]

lpsinger/astropy,pllim/astropy,pllim/astropy,stargaser/astropy,saimn/astropy,StuartLittlefair/astropy,StuartLittlefair/astropy,astropy/astropy,dhomeier/astropy,lpsinger/astropy,mhvk/astropy,MSeifert04/astropy,aleksandr-bakanov/astropy,astropy/astropy,MSeifert04/astropy,aleksandr-bakanov/astropy,saimn/astropy,MSeifert04/astropy,bsipocz/astropy,bsipocz/astropy,mhvk/astropy,stargaser/astropy,lpsinger/astropy,dhomeier/astropy,StuartLittlefair/astropy,stargaser/astropy,larrybradley/astropy,bsipocz/astropy,mhvk/astropy,astropy/astropy,pllim/astropy,MSeifert04/astropy,bsipocz/astropy,astropy/astropy,dhomeier/astropy,lpsinger/astropy,larrybradley/astropy,dhomeier/astropy,dhomeier/astropy,aleksandr-bakanov/astropy,stargaser/astropy,saimn/astropy,larrybradley/astropy,StuartLittlefair/astropy,astropy/astropy,larrybradley/astropy,pllim/astropy,larrybradley/astropy,mhvk/astropy,mhvk/astropy,aleksandr-bakanov/astropy,saimn/astropy,pllim/astropy,saimn/astropy,StuartLittlefair/astropy,lpsinger/astropy