Mark pandoc for expected test failure.
Mark pandoc for expected test failure.

Please see https://github.com/jgm/pandoc/issues/4033.

athanclark/stackage,spencerjanssen/stackage,asr/stackage,phaazon/stackage,mrkkrp/stackage,jonschoning/stackage,Shimuuar/stackage,ethercrow/stackage,massysett/stackage,Daniel-Diaz/stackage,mstksg/stackage,lwm/stackage,mgajda/stackage,garetxe/stackage,iand675/stackage,creichert/stackage,fpco/stackage,int-index/stackage,soenkehahn/stackage,peti/stackage,clinty/stackage,michalkonecny/stackage,fimad/stackage,stackbuilders/stackage,wereHamster/stackage,k0ral/stackage,simonmichael/stackage