added cors to functions

Author: tpiaggio

functions/package.json

@@ -17,6 +17,7 @@
     "@google-cloud/storage": "^4.7.0",
     "camelcase": "^5.3.1",
     "cookie-parser": "^1.4.4",
+    "cors": "^2.8.5",
     "express": "^4.17.1",
     "firebase-admin": "^8.12.1",
     "firebase-function-tools": "^1.1.3",