Can you update a card’s expiration date in wallet?

For information about updating an expiration date, see the following from Change or remove the payment cards that you use with Apple Pay - Apple Support

Update your Apple Pay card number and expiration date

With Apple Pay, your payment card has a unique Device Account Number used to process payments and an expiration date associated with that Device Account Number.

If your card expires or you otherwise get a new card:

• The card number and expiration date linked to the Device Account Number should be updated automatically. 
• If your card issuer doesn’t support these updates, you might need to remove the card and add it again.

I've never needed to update one myself; they have updated auotmatically.