Regression in 1.1.0 - Decode.dict fails for trivial input

The example given for `Json.Decode.dict` is failing in elm/json 1.1.0 with error

     Problem with the given value: { "alice": 42, "bob": 99 } Expecting an OBJECT

The example (https://ellie-app.com/3T4kj4gHJ5Za1)

    decodeString (dict int) "{ \"alice\": 42, \"bob\": 99 }"
