Added

Add Retrieve Trip by ID & Filter Trip by Traveler ID

We have updated two endpoints in the Trips API, you can now get a single trip by ID at trips/{id} and filter trips based on the traveler id at trips?traveler_id={int}.

Respective docs:
https://developers.travelperk.com/reference/retrieve-a-trip-by-id
https://developers.travelperk.com/reference/list-all-trips