Update shulkerboxes.sc to 1.21.6,.7,.8#428

MeeniMc wants to merge 2 commits intognembon:mastergnembon/scarpet:masterfrom

MeeniMc:update/1.21.6/shulkerboxes.scMeeniMc/scarpet:update/1.21.6/shulkerboxes.scCopy head branch name to clipboard