Update csv maintainers.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62122 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

doc/maintainers.rdoc

@@ -212,7 +212,7 @@ Zachary Scott (zzak)
   _unmaintained_
   https://github.com/ruby/cmath
 [lib/csv.rb]
-  James Edward Gray II (jeg2)
+  Kenta Murata (mrkn), Kouhei Sutou (kou)
   https://github.com/ruby/csv
 [lib/fileutils.rb]
   _unmaintained_