update the release info of TiDB Cloud (#7986)#8046

ti-chi-bot merged 3 commits intopingcap:release-5.3pingcap/docs:release-5.3from

ti-chi-bot:cherry-pick-7986-to-release-5.3ti-chi-bot/docs:cherry-pick-7986-to-release-5.3Copy head branch name to clipboard