remove release notes entry from TOC (#3091)#3093

ti-chi-bot[bot] merged 1 commit intopingcap:release-1.3pingcap/docs-tidb-operator:release-1.3from

ti-chi-bot:cherry-pick-3091-to-release-1.3ti-chi-bot/docs-tidb-operator:cherry-pick-3091-to-release-1.3Copy head branch name to clipboard