Add support for the Mageia distro

[dfandrich]

This is basically cargo-culted from existing entries so I don't know if this is
done properly or not. Unfortunately, Mageia vulnerabilities don't seem to be in
the vulnerability database (according to "grype db providers") so I'm not able
to perform a full test.

[wagoodman]

Hi @dfandrich ! The first step to adding support for a new distro is to add a new vunnel provider that reads vulnerability advisories from the intended source. We have some documentation on the best way to get started adding a provider. I don't know much about Mageia, but since it's RPM based there shouldn't be a need to add support in syft to detect packages (🎉 ). Once the vunnel provider is written then it's easier to test the grype changes needed to use that data (we can update this PR later).

Might you be interested in contributing the vunnel provider for this distro?

[dfandrich]

I can probably do that. Is there a reason vunnel doesn't pull from osv.dev? That would eliminate the need for all the Alpine, Debian, GSA, Red Hat, SLES, Ubuntu and Wolfi parsers since they're already in osv.dev.