Updated: ruby-tk 0.4.0

[Daisuke Fujimura via Cygwin-announce]

The following packages have been uploaded to the Cygwin distribution:

* ruby-tk
* ruby-tk-doc

Package summary
* https://cygwin.com/packages/summary/ruby-tk-src.html

Changelog
* https://rubygems.org/gems/tk

Tk interface module for Ruby using tcltklib