Update app.js

@@ -61,7 +61,6 @@ const client = new line.Client(config);
 
 
 // register a webhook handler with middleware
 // register a webhook handler with middleware
 // about the middleware, please refer to doc
 // about the middleware, please refer to doc
-const vision = require('@google-cloud/vision');
 
 
 // Creates a client
 // Creates a client
 var vision = require('google-vision-api-client');
 var vision = require('google-vision-api-client');