Allow activesupport >= 4.0

gitlab_git.gemspec

@@ -12,7 +12,7 @@ Gem::Specification.new do |s|
     'https://gitlab.com/gitlab-org/gitlab_git'
   s.add_dependency("github-linguist", "~> 4.7.0")
-  s.add_dependency("activesupport", "~> 4.0")
+  s.add_dependency("activesupport", ">= 4.0")
   s.add_dependency("rugged", "~> 0.24.0")
   s.add_dependency("charlock_holmes", "~> 0.7.3")
   s.add_development_dependency("listen", "~> 3.0.6")