chore: activate snippet-bot (#1193)
chore: activate snippet-bot (#1193)

See https://github.com/googleapis/repo-automation-bots/tree/master/packages/snippet-bot
GoogleCloudPlatform/php-docs-samples,GoogleCloudPlatform/php-docs-samples,GoogleCloudPlatform/php-docs-samples,GoogleCloudPlatform/php-docs-samples,GoogleCloudPlatform/php-docs-samples