* Rely on encoding tags to determine if string should be dumped as binary.
    https://github.com/ruby/psych/commit/8949a47b8cee31e03e21608406ba116adcf74054
  * Specify "frozen_string_literal: true".
  * Support to binary release for mingw32 platform.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59327 b2dd03c8-39d4-4d8f-98ff-823fe69b080e