feat(auth): add updatePassword method

[brightsider]

Please add updatePassword method

[prescottprue]

You should be able to access through firebase.auth().currentUser.updatePassword directly. There are no needed state updates that I am aware of after updating the user's password - are you needing an action dispatch or state update for something?

[brightsider]

I'm using a firebase error to display errors. If the update password returns an error, then I should to use a custom error handle