[maven-release-plugin] prepare release checkstyle-6.18
[maven-release-plugin] prepare release checkstyle-6.18

rnveach/checkstyle,baratali/checkstyle,sirdis/checkstyle,romani/checkstyle,romani/checkstyle,nikhilgupta23/checkstyle,jochenvdv/checkstyle,bansalayush/checkstyle,sirdis/checkstyle,sharang108/checkstyle,sharang108/checkstyle,MEZk/checkstyle,MEZk/checkstyle,ilanKeshet/checkstyle,liscju/checkstyle,rnveach/checkstyle,sirdis/checkstyle,jochenvdv/checkstyle,sabaka/checkstyle,romani/checkstyle,nikhilgupta23/checkstyle,baratali/checkstyle,rnveach/checkstyle,bansalayush/checkstyle,checkstyle/checkstyle,izishared/checkstyle,rnveach/checkstyle,rnveach/checkstyle,vboerchers/checkstyle,rnveach/checkstyle,liscju/checkstyle,ilanKeshet/checkstyle,jonmbake/checkstyle,jonmbake/checkstyle,jochenvdv/checkstyle,checkstyle/checkstyle,nikhilgupta23/checkstyle,checkstyle/checkstyle,AkshitaKukreja30/checkstyle,jonmbake/checkstyle,sabaka/checkstyle,AkshitaKukreja30/checkstyle,checkstyle/checkstyle,bansalayush/checkstyle,izishared/checkstyle,vboerchers/checkstyle,sharang108/checkstyle,romani/checkstyle,checkstyle/checkstyle,vboerchers/checkstyle,MEZk/checkstyle,checkstyle/checkstyle,liscju/checkstyle,ilanKeshet/checkstyle,baratali/checkstyle,AkshitaKukreja30/checkstyle,sabaka/checkstyle,romani/checkstyle,izishared/checkstyle,romani/checkstyle