Add fold method to TaskEither for consistency with Either

[suojae]

Hi @SandroMaglione, I'm really enjoying using your package, thanks. and while using it, I came across something that I’d like to suggest as an improvement.

In fpdart, Either<L, R> provides both match and fold, but TaskEither<L, R> only has match.

I think this can lead to inconsistencies when working with both Either and TaskEither.

Would it be okay if I add fold to TaskEither to align it with Either?

[shtse8]

I think TaskEither is missing a lot of helpful features that could make it even more powerful. For example, I'm not sure how to zip two TaskEither values effectively in fpdart.

[suojae]

I think TaskEither is missing a lot of helpful features that could make it even more powerful. For example, I'm not sure how to zip two TaskEither values effectively in fpdart.

Oh The zip functionality is a great idea too.