somnia v0.4.0

Added

• then_select on CREATE/UPDATE/DELETE — replaces the manual
  Batch::new().push(mut).push(select).to_surrealql() pattern with a single
  method chain: create.then_select(select). Joins any mutation statement with
  a follow-up SELECT as a ;-separated batch. Available on Create<T>,
  Update<T>, and Delete<T>.