Options should be a kind_of String

From https://github.com/opscode/chef/blob/master/lib/chef/provider/package/rubygems.rb

Line 369-71:
If you have a gem_binary specified, you cannot have options as a Hash.

Line 377-80
If you're using Omnibus, your options should be a String.

Also, there doesn't seem to be any example of how to use options as a hash so it's not clear how to do something like "--force".