* ext/psych/lib/psych.rb: bump version to 2.0.8
* ext/psych/psych.gemspec: ditto.
* ext/psych/psych_emitter.c: ditto.
* ext/psych/psych_parser.c: ditto.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48718 b2dd03c8-39d4-4d8f-98ff-823fe69b080e