message: Update CHANGELOG.md
  Moved performance optimization to public section.
diff: # NEXT RELEASE
  ### Enhancements
  -* None.
  +* Improved query performance for unindexed string columns when the query has a chain of OR conditions.
  + This will improve performance of "IN" queries generated by SDKs.
  + ([PR #3250](https://github.com/realm/realm-core/pull/3250).
  ### Fixed
  * <How to hit and notice issue? what was the impact?> ([#????](https://github.com/realm/realm-core/issues/????), since v?.?.?)
  in every transaction. A new parameter will tell if it is a write- or readtransaction. A new function -
  History::ensure_updated can be called in places where the history object needs to be up-to-date. The
  function will use a flag to ensure that the object is only updated once per transaction.
  -* Optimised queries for unindexed string columns when the query has a chain of OR conditions.
  - This will improve performance of "IN" queries generated by bindings.
  - ([#22](https://github.com/realm/engineering/issues/22).
  ----------------------------------------------
  