Support version 1.7 of the specification

[Edward-Knight]

I couldn't find a ticket to track v1.7 support so I thought I'd put one in. I don't know if there are any existing plans to add support?

See spec release: https://github.com/CycloneDX/specification/releases/tag/1.7
See previous issue for 1.6: #392

[sebtiem]

It looks like there is already a pr for this: #786