= New Features

* A Database#rename_enum_value method has been added to the pg_enum
  extension. It is supported on PostgreSQL 10+:

    DB.rename_enum_value(:enum_type, 'old_name', 'new_name')

= Other Improvements

* The performance of row fetching and type conversion in the
  sqlanywhere adapter has been improved.

* The performance of row fetching in the sqlite adapter has been
  improved.

* Calling Database#drop_table now drops any constraint validations
  metadata for the table if using the constraint_validations
  extension.  However, modifying the table using Database#alter_table
  does not affect the constraint validations metadata.

* The sqlite adapter when used with ruby-sqlite3 1.4.0+ now uses
  SQLite extended result codes for a more accurate determination of
  specific database errors types.

* Performance for typecasting to decimal and floats has been improved
  slightly.

* Performance when merging hashes has been improved slightly.