Log Message:
databases/ruby-sequel: update to 5.51.0

5.51.0 (2021-12-01)

* Make eager loading via tactical_eager_loading no longer modify objects who
  already have a cached value for the association (jeremyevans)
* Make association cloning handle cases where clone association sets
  different :class option than cloned association (jeremyevans)
* Make column schema entries on MySQL include an :extra entry for the Extra
  column in DESCRIBE output (bschmeck) (#1791)
* Update mock PostgreSQL adapter to default to PostgreSQL 14 instead of
  PostgreSQL 9.5 (jeremyevans)
* Support Dataset#with_recursive :search and :cycle options on PostgreSQL
  14+ for result ordering and cycle detection (jeremyevans)
* Avoid method redefined verbose mode warnings in lazy_attributes plugin
  (jeremyevans)