hsdns: enable builds again
hsdns: enable builds again

The package is disabled due to https://github.com/fpco/stackage/issues/840, but
that issue was fixed 9 months ago!

mrkkrp/stackage,jaspervdj/stackage,creichert/stackage,soenkehahn/stackage,michalkonecny/stackage,spencerjanssen/stackage,Daniel-Diaz/stackage,simonmichael/stackage,k0ral/stackage,fpco/stackage,Shimuuar/stackage,ygale/stackage,brendanhay/stackage,lwm/stackage,garetxe/stackage,ethercrow/stackage,int-index/stackage,clinty/stackage,fimad/stackage,l29ah/stackage,jonschoning/stackage,GregorySchwartz/stackage,codedmart/stackage,mgajda/stackage,mstksg/stackage,alanz/stackage,iand675/stackage,massysett/stackage,DanielG/stackage,wereHamster/stackage,phaazon/stackage,judah/stackage,christiaanb/stackage,phadej/stackage,asr/stackage,stackbuilders/stackage,peti/stackage,athanclark/stackage