metanorma-un.gemspec in metanorma-un-0.12.14 vs metanorma-un.gemspec in metanorma-un-0.12.15

@@ -41,6 +41,7 @@
   spec.add_development_dependency "rspec", "~> 3.6"
   spec.add_development_dependency "rubocop", "~> 1.5.2"
   spec.add_development_dependency "sassc", "2.4.0"
   spec.add_development_dependency "simplecov", "~> 0.15"
   spec.add_development_dependency "timecop", "~> 0.9"
+  spec.add_development_dependency "xml-c14n"
 end