app.yaml s/python/nodejs in comment (#562)
app.yaml s/python/nodejs in comment (#562)

Minor nit surfaced in bug
GoogleCloudPlatform/nodejs-docs-samples,GoogleCloudPlatform/nodejs-docs-samples,JustinBeckwith/nodejs-docs-samples,JustinBeckwith/nodejs-docs-samples,JustinBeckwith/nodejs-docs-samples,GoogleCloudPlatform/nodejs-docs-samples,GoogleCloudPlatform/nodejs-docs-samples