Laravel Tymon\JWTAuth - change credential authentication attributes to "Email" and "Password"

I want to add jwt-auth for an existing Laravel application. In the current application, it uses "Username", "Email" and "Password" fields inside users table to store credentials.

But in jwt-auth credential authentication working for ("email" | "username") and "password" fields combinations. (lowercase column names). How can I make it work with capitalized column names?

via Chebli Mohamed