x/vulndb: support CVE schema v5.0 in worker

[julieqiu]

Add support for collectionUrl and packageName in cmd/cvetriage. This is introduced in CVE schema v5.0.

CVEProject/cve-schema@3208d6d

https://github.com/CVEProject/cve-schema/blob/master/schema/v5.0/docs/versions.md

[jba]

v5.0 is a radical change from v4.0. Even the basic object keys are in a different format: dataVersion vs. data_version. I think we'll need a completely new set of Go structs for v5.

Currently, no CVEs use v5.

[julieqiu]

We can probably hold off on implementing this until we see actual v5.0 CVEs in the cvelist repo.