The duplicate attribute is case insensitive

[windowdotonload]

• [x] I am running the latest version
• [x] I checked the documentation and found no answer (Nothing in the docu for 'loadOriginalValues' gives an clue that HTML Tag like Text gets removed the input should accept like in the running demo)
• [x] I checked to make sure that this issue has not already been filed

expected

The duplicate property can be a Boolean or an Object

For example:

new Tagify(input, {
   duplicates: {
      disallow: true,
      caseSensitive: true
   }
})

It is case-sensitive when detecting duplicates of tags