chore(deps): update dependency firebase-functions-test to v3

Author: renovate[bot]

functions/package.json

@@ -17,7 +17,7 @@
     "firebase-functions": "3.15.7"
   },
   "devDependencies": {
-    "firebase-functions-test": "0.3.2"
+    "firebase-functions-test": "3.1.0"
   },
   "private": true
 }