Add AlmaLinux 9 as supported OS

What does this MR do and why?

Add AlmaLinux 9 as supported OS

- GitLab 16.0 release will ship with AlmaLinux 9 support.

Related https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/6878

Related https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/7828

Changelog: added

Signed-off-by: Robert Marshall <rmarshall@gitlab.com>

Related Update documentation on new Alma Linux 9 Packages (omnibus-gitlab#7828 - closed)

MR acceptance checklist

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