fix sideloading link to developer.zendesk.com
fix sideloading link to developer.zendesk.com

airbnb/zendesk_api_client_rb,airbnb/zendesk_api_client_rb,devpuppy/zendesk_api_client_rb,zendesk/zendesk_api_client_rb,devpuppy/zendesk_api_client_rb,airbnb/zendesk_api_client_rb,jademcgough/zendesk_api_client_rb