fix: minor import fix (#3632)

Author: pattishin

security-center/snippets/v1/createNotificationConfig.js

@@ -19,7 +19,7 @@ function main(
   pubsubTopic = 'projects/{your-project}/topics/{your-topic}'
 ) {
   // [START securitycenter_create_notification_config]
-  // npm install @google-cloud/security-center/
+  // npm install '@google-cloud/security-center'
   const {SecurityCenterClient} = require('@google-cloud/security-center');
 
   const client = new SecurityCenterClient();