Fix private method visibility in container registry

app/services/auth/container_registry_authentication_service.rb

@@ -28,6 +28,10 @@ module Auth
       token.encoded
     end
 
+    def self.token_expire_at
+      Time.now + current_application_settings.container_registry_token_expire_delay.minutes
+    end
+
     private
 
     def authorized_token(*accesses)
@@ -35,7 +39,7 @@ module Auth
       token.issuer = registry.issuer
       token.audience = params[:service]
       token.subject = current_user.try(:username)
-      token.expire_time = ContainerRegistryAuthenticationService.token_expire_at
+      token.expire_time = self.class.token_expire_at
       token[:access] = accesses.compact
       token
     end
@@ -81,9 +85,5 @@ module Auth
     def registry
       Gitlab.config.registry
     end
-
-    def self.token_expire_at
-      Time.now + current_application_settings.container_registry_token_expire_delay.minutes
-    end
   end
 end