async.gemspec in async-0.10.0 vs async.gemspec in async-0.11.0

@@ -21,10 +21,10 @@
 	spec.require_paths = ["lib"]
 	spec.has_rdoc      = "yard"
 	
 	spec.required_ruby_version = ">= 2.2.6"
 
-	spec.add_runtime_dependency "nio4r", "~> 2"
+	spec.add_runtime_dependency "nio4r"
 	spec.add_runtime_dependency "timers", "~> 4.1"
 	
 	spec.add_development_dependency "bundler", "~> 1.3"
 	spec.add_development_dependency "process-daemon", "~> 1.0.0"
 	spec.add_development_dependency "rspec", "~> 3.4.0"