Fix Money\Currency Json serialization

[jaumebecks]

Currency JSON serialization should return an indexed array, as it should be treated as an object in JSON. Therefore, when serializing a Money object, the result should be like

"moneyInstance": {
    "amount": "1000",
    "currency": { 
        "code": "EUR"
    }
}

Instead of

"moneyInstance": {
    "amount": "1000",
    "currency":  "EUR"
}

[sagikazarmark]

Currency JSON serialization should return an indexed array, as it should be treated as an object in JSON.

I don't think that's necessarily true. The format is arbitrary, nothing says the currency has to be an object. Additionally, this is a breaking change.

[jaumebecks]

@sagikazarmark It's true that it is a breaking change, and that shouldn't be an impediment to try to improve the code.

And following the current Entity structure, the default Object formatting should respect the JSON serialization. Money::$currency is a Currency object, and should be reflected as so in JSON, otherwise serialization/deserialization need special serializers/deserializers to manipulate the data. Another thing is that it's intended to apply such change

[frederikbosch]

Unnecessary breaking change. Closing.