ndeslandesupgrade

Results 2 issues of ndeslandesupgrade

Add support for endpoint /groups/assignable https://developer.zendesk.com/api-reference/ticketing/groups/groups/#list-assignable-groups

- [x] I am on the [latest](https://github.com/sdispater/pendulum/releases/latest) Pendulum version. - [x] I have searched the [issues](https://github.com/sdispater/pendulum/issues) of this repo and believe that this is not a duplicate. - **OS version...