write_xlsx.gemspec in write_xlsx-0.69.0 vs write_xlsx.gemspec in write_xlsx-0.70.0

@@ -21,7 +21,8 @@
     "LICENSE.txt",
     "README.rdoc"
   ]
 
   gem.add_runtime_dependency(%q<rubyzip>, [">= 0"])
+  gem.add_development_dependency(%q<simplecov>) if RUBY_VERSION >= "1.9"
 end