Fix Rounding-Issues with shipping costs and refunds

[samuelmente]

We had an issue, where an unrounded amount for shipping was sent to Payone API resulting in an error. Woocommerce seems to be returning a rounded number for "shipping_total" but an unrounded amount for "shipping_tax" resulting in a false amount when adding. Adding round() will prevent this issue from causing problems.
Example: 1,95 shipping cost will falsely be sent to the API as 195.1345.

[janteuber]

The change from the PR does make sense as it is. The round() function is indeed already used in other places. I would only modify the line like this:

'pr' =\> (int) round( 100 \* ( $refund_data\['shipping_total'\] + $refund_data\['shipping_tax'\] ) ),

This is because the return value of round() is a float, but we also want to ensure that it is an int.

[samuelmente]

You are right. I added a change to include the int declaration.