Change API urls to plural form

Co-authored-by: Jeremy Stretch <jstretch@ns1.com>

netbox/ipam/api/urls.py

@@ -46,8 +46,8 @@ router.register('service-templates', views.ServiceTemplateViewSet)
 router.register('services', views.ServiceViewSet)
 
 # L2VPN
-router.register('l2vpn', views.L2VPNViewSet)
-router.register('l2vpn-termination', views.L2VPNTerminationViewSet)
+router.register('l2vpns', views.L2VPNViewSet)
+router.register('l2vpn-terminations', views.L2VPNTerminationViewSet)
 
 app_name = 'ipam-api'