Update api-version to 1.21 for Minecraft 1.21.10 compatibility#2

shikendon wants to merge 1 commit intomaster-forkphateio/ViewDistanceTweaks:master-forkfrom

claude/minecraft-plugin-compatibility-check-01ScxwuF9PdiUqae2Vc5fWArphateio/ViewDistanceTweaks:claude/minecraft-plugin-compatibility-check-01ScxwuF9PdiUqae2Vc5fWArCopy head branch name to clipboard