Bumping xdan-datetimepicker-rails to 2.5.1

Signed-off-by: Chris Desch <cdesch@gmail.com>

Author: cdesch

active_admin_datetimepicker.gemspec

@@ -19,7 +19,7 @@ Gem::Specification.new do |spec|
   spec.executables   = spec.files.grep(%r{^bin/}) { |f| File.basename(f) }
   spec.require_paths = ["lib"]
 
-  spec.add_dependency "xdan-datetimepicker-rails", "~> 2.4"
+  spec.add_dependency "xdan-datetimepicker-rails", "~> 2.5.1"
   spec.add_development_dependency "bundler", "~> 1.8"
   spec.add_development_dependency "rake", "~> 10.0"