Non-alfanumeric values in SKU gives product references that are invalid

[developedbyme]

For example / or non latin characters are not filtered out when generating the product reference and gives the error:

{"type":"https://api.payex.com/psp/errordetail/inputerror","title":"Error in input data","status":400,"instance":"https://api.payex.com/psp/probleminstance/00-cf7685ff6efc4019a879d7aa496f16d3-a2a329b1c3bc722e-01","detail":"Input validation failed, error description in problems node!","problems":[{"name":"PaymentOrder.OrderItems[0].Reference","description":"The field Reference must match the regular expression '[\w-]*'."}]}