Update google-cloud-error_reporting generated files (#2622)
Update google-cloud-error_reporting generated files (#2622)

* Add synth.metadata file.
googleapis/google-cloud-ruby,googleapis/google-cloud-ruby,quartzmo/google-cloud-ruby,blowmage/gcloud-ruby,dazuma/google-cloud-ruby,dazuma/google-cloud-ruby,googleapis/google-cloud-ruby,quartzmo/google-cloud-ruby,googleapis/google-cloud-ruby,quartzmo/google-cloud-ruby,dazuma/google-cloud-ruby,dazuma/google-cloud-ruby,dazuma/google-cloud-ruby,dazuma/google-cloud-ruby,quartzmo/google-cloud-ruby,googleapis/google-cloud-ruby,quartzmo/google-cloud-ruby,quartzmo/google-cloud-ruby,googleapis/google-cloud-ruby