Are there really no actual schema changes between 1.3.0 and 1.7.0? I would have expected to see something change in the format of the advisory.

The version is semantic, so any breaking changes that'd require us to change would be in a v2 - the changes in these minors are primarily additions of new enum and type-based stuff like prefixes, ecosystems, and severity formats (e.g. CVSS v4.0) ; I'm pretty sure the main new feature is the last_affected event type 🤷

(fwiw too the schema repo is also home to a few auxiliary stuff like binding libraries for Go and tools, which are versioned as well - so it's a little messy to say exactly what changed about the schema specifically 😅)