post
https://api.momence.com/api/v2/member/saved-payment-methods
This endpoint returns a temporary pre-authenticated URL that allows user to add a payment method.
Redirect user to that URL, which will allow them to add a payment method using a Momence-hosted app.
The URL will be valid for 3600 seconds.
After the user finishes adding the payment method, they will get redirected to the URL provided.