io/console: 0.4.2

* ext/io/console/io-console.gemspec: bump to 0.4.2.  now explicitly
  requires ruby 1.9.3 or later.  [Bug #7847]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39272 b2dd03c8-39d4-4d8f-98ff-823fe69b080e