authentication.erb in gapic-generator-cloud-0.10.0

- old
+ new

@@ -1,6 +1,6 @@
 <%- assert_locals gem -%>
-<%- service = gem.first_non_common_service -%>
+<%- service = gem.first_non_common_service.usable_service_presenter -%>
 <%- assert_locals service -%>
 # Authentication
 
 In general, the <%= gem.name %> library uses
 [Service Account](https://cloud.google.com/iam/docs/creating-managing-service-accounts)