Ruby io_splice 4.4.1 - minor updates

This release fixes mismatched indentation warnings in
Ruby 2.6+.  There are also some minor doc updates.

Of course, all the relevant functionality is also in the
"sleepy_penguin" RubyGem.  So chances are you won't need
this package and increase overhead from DSOs(*)

4 changes since v4.4.0

      io/splice: fix mismatched indentation warnings
      pkg.mk: build system updates
      doc: update URLs to HTTPS and remove refs to mail software
      README: add a note on sleepy_penguin providing splice + tee

(*) https://udrepper.livejournal.com/8790.html