Adjust dependencies and add check

• Adjust dependencies
  • Add dependency on ruby-fiber-annotation.
  • Dependency on fiber-annotation was added upstream in https://github.com/socketry/async/commit/01e6baea73fc94158644d6442593d9707ece98a8.
  • Remove dependency on ruby-nio4r.
  • Dependency on nio4r was removed upstream in https://github.com/socketry/async/commit/00de67c38e1ffeb40785901c353aeabb54013ade.
  • Remove dependency on ruby-timers.
  • Dependency on timers was removed upstream in https://github.com/socketry/async/commit/a09253eca2046b1a917a67a844c337d19d9c963d.
• Add check