[DRE-maint] Bug#965981: CVE-2020-5238

[Moritz Muehlenhoff]

Package: ruby-commonmarker
Severity: important
Tags: security

This was assigned CVE-2020-5238
https://github.com/github/cmark-gfm/security/advisories/GHSA-7gc6-9qr5-hc85
https://github.com/github/cmark-gfm/commit/85d895289c5ab67f988ca659493a64abb5fec7b4

And ruby-commonmarker seems to embed a copy of cmark-gfm.

Cheers,
        Moritz