devel/ruby-io-event: update to 1.2.3

pkgsrc change: remove redundant RUBY_VERSIONS_ACCEPTED definition.

1.2.3 (2023-07-26)

* Add test for zero length write. (#60)
* Fix pipe test on BSD systems. (#62)
* Fix Select selector backend per-IO waiter queue handling (#63)
* Add some comments regarding the new implementation.
* Modernize gem.

(taca)