JSON Content-types for responses

Hello 👋

Per our discussion [here](https://developers.tabapay.com/discuss/62a41c9cc84c6100304af3f0) we discussed TabaPay updating all API endpoints' content-type headers to JSON.

I was wondering if there's an update to that. We're refactoring our network module and finding it difficult to override our responses from TabaPay accordingly.

Thanks!