Ruby 3.2 support

[yabenatti]

CFPropertyList doesn't work with Ruby 3.2.

Error:

 NoMethodError: undefined method `exists?' for File:Class
/.gem/ruby/3.2.0/gems/CFPropertyList-3.0.5/lib/cfpropertylist/rbCFPropertyList.rb:378:in `save'

The method File.exists? has been deprecated since Ruby 2.1.0 and was removed on Ruby 3.2.0.

[ckruse]

Thanks for reporting! Will release a new version :-)

[yabenatti]

Thank you!