Version bump `0.8.6` → `0.8.7`.
### Added
- R binding: a *Getting started* vignette and a synthetic `sample_ohlcv` example dataset, giving new users a runnable, self-contained walkthrough and populating the R-universe Articles and Datasets tabs. The vignette's code is exercised in CI so a broken example is caught before the published build. (#262)
Bump touches the manual release touchpoints only; docs/webpage version strings are left to `sync-about.yml` on the tag.
kingchenc
b1653e2107