v3(style): fix rubocop warnings

[#175662475](https://www.pivotaltracker.com/story/show/175662475)

Author: pivotal-marcela-campo

app/actions/service_credential_binding_app_create.rb

@@ -47,7 +47,7 @@ def precursor(service_instance, app: nil, name: nil, volume_mount_services_enabl
 
       def complete_binding_and_save(binding, binding_details, last_operation)
         binding.save_with_attributes_and_new_operation(
-          binding_details.symbolize_keys().slice(*PERMITTED_BINDING_ATTRIBUTES),
+          binding_details.symbolize_keys.slice(*PERMITTED_BINDING_ATTRIBUTES),
           {
             type: 'create',
             state: last_operation[:state],

spec/request/service_credential_bindings_spec.rb

@@ -1383,7 +1383,7 @@ def check_filtered_bindings(*bindings)
                   syslog_drain_url: syslog_drain_url,
                   credentials: credentials,
                   parameters: parameters,
-                  service_id:'extra-field-service_id-should-ignore',
+                  service_id: 'extra-field-service_id-should-ignore',
                   name: 'extra-field-name-should-not-update',
                 }
               end