fix: drop support for node.js 4.x and 9.x (#46)
fix: drop support for node.js 4.x and 9.x (#46)

* fix: drop support for node.js 4.x and 9.x

* fix my blunder

GoogleCloudPlatform/nodejs-docs-samples,GoogleCloudPlatform/nodejs-docs-samples,GoogleCloudPlatform/nodejs-docs-samples,GoogleCloudPlatform/nodejs-docs-samples