merge revision(s) 62422: [Backport #14481]

Merge RubyGems 2.7.6 from upstream.

	  It fixed some security vulnerabilities.

	  http://blog.rubygems.org/2018/02/15/2.7.6-released.html

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_4@62434 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/rubygems/commands/owner_command.rb

@@ -62,7 +62,7 @@ permission to.
     end
 
     with_response response do |resp|
-      owners = YAML.load resp.body
+      owners = Gem::SafeYAML.load resp.body
 
       say "Owners for gem: #{name}"
       owners.each do |owner|