Update libxml-ruby to 2.8.0
Update libxml-ruby to 2.8.0

Config has been deprecated in ruby 2.2
https://github.com/xml4r/libxml-ruby/commit/0bdfffcdd53a40bd866b10b4692e23da6a020d88

catarse/catarse_moip,catarse/catarse_moip,catarse/catarse_moip