Update dependency firebase-admin to v11

Author: mend-for-github-com[bot]

firebase/JavaScript/functions/package.json

@@ -17,7 +17,7 @@
   "dependencies": {
     "@google-cloud/dialogflow": "^2.0.0",
     "@google-cloud/pubsub": "^1.7.3",
-    "firebase-admin": "^8.9.0",
+    "firebase-admin": "^11.0.0",
     "firebase-functions": "^3.3.0",
     "nexmo": "^2.7.0-beta-1"
   },