The colon separator(`:`) of `--security-opt` flag was deprecated in 1.11.0. However, the subtitle in deprecated docs is missing so it is placed under the same subtitle as the deprecated `-e` and `--email` flags. This fix adds the missing subtitle in deprecated docs. Signed-off-by: Yong Tang <yong.tang.github@outlook.com> Upstream-commit: 018c22880d594b1de06216aa05186f2ebe9a1e9c Component: engine