When where contains values with underscores, those will be incorrectly changed when calling to_param

[mentalic]

For example, when searching for items with where (where: ["Code.ToUpper() == "ITEM_WITH_UNDERSCORE""]) will be changed to ITEMWITHUNDERSCORE https://github.com/XeroAPI/xero-ruby/blob/53f0118dab4ecaf73d0f2edb3248fbc42fdc2ba0/lib/xero-ruby/api_client.rb#L666