v0.6.3 — Options flow for switching engines / data sources

v0.6.3 — Options flow for switching engines / data sources

Added

• The integration now exposes an OptionsFlow so existing config
  entries can be reconfigured via Settings → Devices & Services → Rain
  Warner → Configure. Switching the nowcast engine, data source or
  monitoring radius no longer requires deleting and re-adding the
  integration (which would wipe the persisted rain statistics). Picking
  the pysteps engine here triggers the same automatic dependency
  install introduced in 0.6.2.