Update to 1.868
    
    - New upstream release 1.868
      - Bug fix for UTF-8 issues during inter-process communication
        - This update required undoing optimizations specific to scalar args
        - Essentially, IPC involves serialization for everything going forward
        - Install Sereal::Encoder and Sereal::Decoder for better performance
      - Improved MCE::Hobo with threads-like detach capability (see POD)
      - Resolved MCE::Hobo stalling MCE::Shared::Server during global clean-up
      - Improved IPC in MCE::Shared::Queue with permanent fast-like dequeue
        including dequeue_nb; going forward, the fast and barrier options are
        silently ignored if specified (i.e. no-op)
      - Improved IPC performance on Linux
      - Completed threads-like detach capability in MCE::Hobo