kgio 2.11.4

This release fixes compatibility with GC.compact on Ruby 3.x.
Thanks to Ngan Pham for the patch and Aaron Patterson for the
feedback:

  https://yhbt.net/kgio-public/CAAvYYt5Z5f2rMuXO5DMpR1-6uRvu_gXKDvqcyoZ+oNcLiTH39g@mail.gmail.com/T/

kgio remains obsolete and deprecated, and it's primary dependent
will be updated to not depend on it in the future.