Fix typo (#908)

Author: rmschindler

quickstarts/uppercase-firestore/functions/index.js

@@ -17,7 +17,7 @@
 
 // [START all]
 // [START import]
-// The Cloud Functions for Firebase SDK to create Cloud Functions and setup triggers.
+// The Cloud Functions for Firebase SDK to create Cloud Functions and set up triggers.
 const functions = require('firebase-functions');
 
 // The Firebase Admin SDK to access Firestore.