Bump to 5.2.1

[ci skip]

NEWS

+5.2.1 (2018-01-25):
+
+* Bugfix: Fix copying files on Windows. (#2532)
+
 5.2.0 (2018-01-23):
 5.2.0 (2018-01-23):
 
 
 * Security: Remove the automatic loading of URI adapters. Some of these
 * Security: Remove the automatic loading of URI adapters. Some of these

lib/paperclip/version.rb

 module Paperclip
 module Paperclip
   unless defined?(Paperclip::VERSION)
   unless defined?(Paperclip::VERSION)
-    VERSION = "5.2.0".freeze
+    VERSION = "5.2.1".freeze
   end
   end
 end
 end