Merge branch 'cb-clarify-rhel-7-deprecation' into 'master'

Clarify deprecation for Red Hat Enterprise Linux 7

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/173537



Merged-by: Evan Read <eread@gitlab.com>
Approved-by: Dilan Orrino <dorrino@gitlab.com>
Approved-by: Evan Read <eread@gitlab.com>
Co-authored-by: Clemens Beck <cbeck@gitlab.com>