Search sort by descending by default is not supported

[cserkaran]

As we can see in the zendesk rest api implementation, the listing of search results sort_order is desc by default. The client has a bug where it is not considered, and even on passing sort order as descending,
sort is still done by descending.

[cserkaran]

Have a fix ready. Raising a PR soon.

[hjaltethor]

Thanks for the PR! I've just merged it and will be releasing a new version of the client later today.