asciidoctor-iso.gemspec in asciidoctor-iso-0.9.0 vs asciidoctor-iso.gemspec in asciidoctor-iso-0.9.1

@@ -41,6 +41,7 @@
   spec.add_development_dependency "rake", "~> 12.0"
   spec.add_development_dependency "rspec", "~> 3.6"
   spec.add_development_dependency "rubocop", "~> 0.50"
   spec.add_development_dependency "simplecov", "~> 0.15"
   spec.add_development_dependency "timecop", "~> 0.9"
+  spec.add_development_dependency "metanorma"
 end