[REQUIRED] Environment info

firebase-tools: 14.12.1

Platform: All plafroms

[REQUIRED] Test case

Deploy firebase deploy --config firebase.json

Test database rules file

{
  "rules": {
    "users": {
      "$uid": {
        ".read": "$uid === auth.uid",
        ".write": "$uid === auth.uid"
      }
    }
  }
}

[REQUIRED] Steps to reproduce

On firebase-tools versions 14.10.1 and before this works fine. On 14.12.1 I get the below error. This same config file has been working for years with no issue

[REQUIRED] Expected behavior

Rules deploy

[REQUIRED] Actual behavior

i  deploying database, storage, firestore, functions
i  database: checking rules syntax...

Error: Syntax error in database rules:

1:2: Expected 'rules' property.