security/cargo-audit: version 0.20.0
https://github.com/rustsec/rustsec/blob/main/cargo-audit/CHANGELOG.md#0200-2024-02-16
Also, make ca_root_nss a RUN_DEPENDS to workaround
https://github.com/rustsec/rustsec/issues/1137
PR: 279260
Approved by: mikael (maintainer)