Fix link for prerequisites (#587)
Fix link for prerequisites (#587)


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