fix(isBIC): add XK to accepted BIC country codes

[import-brain]

Adds the country code XK (Republic of Kosovo) to isBIC's allowed country codes

closes #2045

Checklist

• PR contains only changes related; no stray files, etc.
• README updated (where applicable)
• Tests written (where applicable)

[codecov]

Codecov Report

Base: 100.00% // Head: 100.00% // No change to project coverage 👍

Coverage data is based on head (6df1853) compared to base (6dba289).
Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

@@            Coverage Diff            @@
##            master     #2046   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          105       105           
  Lines         2334      2335    +1     
  Branches       586       586           
=========================================
+ Hits          2334      2335    +1     

Impacted Files	Coverage Δ
src/lib/isBIC.js	100.00% <100.00%> (ø)

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[ST-DDT]

Maybe extract the country code to its own variable instead of resolving it twice?

[JohnIrle]

Would it be better to add the country code to the Set of country codes in isISO21661Alpha2.js?

[WikiRik]

No, it's not part of that list. It's a special code used only for BIC (in the scope of this project)

[WikiRik]

Could you add some tests for the XK BIC? Preferably some valid and invalid.

You can add them to the current test;

validator.js/test/validators.test.js

Lines 5070 to 5088 in 753c29d

	it('should validate BIC codes', () => {
	test({
	validator: 'isBIC',
	valid: [
	'SBICKEN1345',
	'SBICKEN1',
	'SBICKENY',
	'SBICKEN1YYP',
	],
	invalid: [
	'SBIC23NXXX',
	'S23CKENXXXX',
	'SBICKENXX',
	'SBICKENXX9',
	'SBICKEN13458',
	'SBICKEN',
	],
	});
	});

[WikiRik]

Thanks!

[profnandaa]

LGTM, thanks for your contrib 🎉