Base the API diff baseline version on the latest release (original) (raw)

The api-diff workflow (.github/workflows/api-diff.yml) hardcodes the baseline version (1.5.1) that PR artifacts compare against. After each release this drifts and needs a manual bump.

Derive the baseline from the latest release (latest git tag / GitHub release) instead of hardcoding it, or add a post-release step that bumps it automatically.

Follow-up from #2168.