Fix deprecation warning [(#1801)](https://github.com/GoogleCloudPlatform/python-docs-samples/issues/1801)
Fix deprecation warning [(#1801)](https://github.com/GoogleCloudPlatform/python-docs-samples/issues/1801)

logging.warn -> logging.warning to fix "DeprecationWarning: The 'warn' function is deprecated, use 'warning' instead"
googleapis/python-logging,googleapis/python-logging