fix: Remove 'id' from the Card update payload.

[jbottigliero]

Although the id parameter is listed as "Required" in the Stripe documentation. Passing the id as a parameter will result in the following error:

 %Stripe.Error{
   code: :invalid_request_error,
   extra: %{
     http_status: 400,
     param: :id,
     raw_error: %{
       "message" => "A parameter provided in the URL (id) was repeated as a GET or POST parameter. You can only provide this information as a portion of the URL.",
       "param" => "id",
       "type" => "invalid_request_error"
     }
   },
   message: "A parameter provided in the URL (id) was repeated as a GET or POST parameter. You can only provide this information as a portion of the URL.",
   request_id: nil,
   source: :stripe,
   user_message: nil
 }}

This update removes the id from the payload similar to customer.

Removing :id from the guard is also an option (I ran into this issue based on Dialyzer failures).

The test I've added will assert {:error, _}without this change.

[coveralls]

Coverage remained the same at 88.467% when pulling 3d3545a on jbottigliero:fix-card-update into 560dbf4 on code-corps:master.

[snewcomer]

Very nice PR! Thank you 👏