Fix typo in link to prerequisites (#392)
Fix typo in link to prerequisites (#392)


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