Fix "maintainng" typo in MAINTAINERS.md
Fix "maintainng" typo in MAINTAINERS.md

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