ID sync from GitHub Security Advisories is broken due to CVSSv4 vectors

[amousset]

The advisories ID sync job fails with:

error: error loading advisory DB repo from .: RustSec error: error parsing /tmp/osv/GHSA-2wq5-g96f-mv3v.json: unknown variant `CVSS_V4`, expected `CVSS_V3` at line 56 column 23

Since GitHub started adding CVSS v4 scores. Once the cvss crate supports them (https://github.com/rustsec/rustsec/pull/1285), we can add support to the OSV reader and other rustsec tooling.