add sdkVersion to ThreeDS2RequestData

[daanvinken]

Description
Added the SDKVersion to the ThreeDS2RequestData as specified in the API explorer here.

Tested scenarios
Made a request to /authorise containing the SDKVersion:

"merchantAccount" : "DaanVinken",
   "reference" : "1234565",
   "shopperInteraction" : "Ecommerce",
   "skinCode" : "pub.v2.8716439713203510.fTL__BlhCNKwC6i_9DcKdjA762vf3X_zG0sv8I0giY8",
   "threeDS2RequestData" : {
      "deviceChannel" : "browser",
      "notificationURL" : "https:\/\/docs.adyen.com",
      "sdkVersion" : "2.2.5"
   },
   "card" : {
      "holderName" : "Checkout Shopper PlaceHolder"
   }

Received 200 with CheckoutPaymentsAction (offer LMLSDDF59L2GWR82).

Fixed issue:
NA

[wboereboom]

Looks good. got 1 suggestion, but will approve after that's fixed