jekyll-sitemap.gemspec in jekyll-sitemap-1.3.1 vs jekyll-sitemap.gemspec in jekyll-sitemap-1.4.0

@@ -21,10 +21,9 @@
   spec.required_ruby_version = ">= 2.3.0"
 
   spec.add_dependency "jekyll", ">= 3.7", "< 5.0"
 
   spec.add_development_dependency "bundler"
-  spec.add_development_dependency "jekyll-last-modified-at", "~> 1.0"
   spec.add_development_dependency "rake"
   spec.add_development_dependency "rspec", "~> 3.0"
   spec.add_development_dependency "rubocop-jekyll", "~> 0.4"
 end