Userpoints POST rest resource (api/userpoints) doesn't work

Problem/Motivation

Userpoints POST rest resource (api/userpoints) doesn't work when we use user points module 2.x version.

Steps to reproduce

1. 1) Enable the rest resource of 'api/userpoints'
2. 2) Try to perform add operation using the end point
3. 3) User response we get is:
   

   {
       "message": "No route found for \"POST /api/userpoints\""
   }

Proposed resolution

Change the uri_paths from https://www.drupal.org/link-relations/create to create