Bump version to 1.4.0. New minor version.

1.4.0 adds support for Contacts and Groups.

Author: epels

lib/messagebird.rb

@@ -2,7 +2,7 @@
 $:.unshift(libdir) unless $:.include?(libdir)
 
 module MessageBird
-  CLIENT_VERSION = '1.3.3'
+  CLIENT_VERSION = '1.4.0'
   ENDPOINT       = 'https://rest.messagebird.com'
 end