Issue with generation for Address within Kosovo

[hellmer1234]

Type of issue

[ X ] Bug
[ ] Question (e.g. about handling/usage)
[ ] Request for new feature/improvement

Expected Behavior

When i put XK as country code within a contact address, i could generate a valid swissQRCode
as XK is a valid ISO 3166-1 alpha-2 code for Kosovo (https://laendercode.net/fr/country/xk)

Current Behavior

When trying to use XK as country code, i encounter the following error :
Country must be a valid "two letter" country code as defined by ISO 3166-1, but it isn't.
Stacktrace: at QRCoder.PayloadGenerator.SwissQrCode.Contact..ctor(String name, String zipCode, String city, String country, String streetOrAddressline1, String houseNumberOrAddressline2, AddressType addressType)

Possible Solution (optional)

In private static HashSet ValidTwoLetterCodes() add the ISO-3166-1 code for Kosovo (as describe here :https://laendercode.net/fr/country/xk)

Steps to Reproduce (for bugs)

When trying the following strings in the payload, i encounter an error :

• Country : XK

Your Environment

• Compiled from source or NuGet package?: Nuget Package
• Version used : QRCoder 1.3.9

[codebude]

XK is not part of the list, since it isn't part of the official ISO standard as far as I can see. Check it out here: https://www.iso.org/obp/ui/#search/code/

The SwissQRCode standard in addition says that the country code must be ISO-3166-1 compliant. So technically my implementation is correct. Nevertheless I see the need and I also saw, that most organizations agreed on using XK as long as there is no official code, so I'll add it to the list soon.

[hellmer1234]

Many thanks for all the job @codebude
Tested and deployed into production.
Well done !