Add warning about updating webhook events.
|## Release 6.1.3|
|**You need to Fix/Create webhook after installing this update to add the `charge.captured` event to the list of events sent to the webhook.**|
|* Handle charge.succeeded/charge.captured when no customer_id is provided - fixes 400 errors / missing customer_id.|
|* Remove invalid setting of customer on paymentIntent (no user impact).|
|* Small improvements to Stripe Plan code (no user impact).|