Add upper bound for autoexporter.
Add upper bound for autoexporter.

Please see https://github.com/tfausak/autoexporter/issues/4.

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