feat(isCreditCard): Fixed regex for Union Pay Credit cards with 81 range (#1715)

* Fixes #1680

* Added Tests

Author: shreyassai123

src/lib/isCreditCard.js

@@ -1,7 +1,7 @@
 import assertString from './util/assertString';
 
 /* eslint-disable max-len */
-const creditCard = /^(?:4[0-9]{12}(?:[0-9]{3,6})?|5[1-5][0-9]{14}|(222[1-9]|22[3-9][0-9]|2[3-6][0-9]{2}|27[01][0-9]|2720)[0-9]{12}|6(?:011|5[0-9][0-9])[0-9]{12,15}|3[47][0-9]{13}|3(?:0[0-5]|[68][0-9])[0-9]{11}|(?:2131|1800|35\d{3})\d{11}|6[27][0-9]{14})$/;
+const creditCard = /^(?:4[0-9]{12}(?:[0-9]{3,6})?|5[1-5][0-9]{14}|(222[1-9]|22[3-9][0-9]|2[3-6][0-9]{2}|27[01][0-9]|2720)[0-9]{12}|6(?:011|5[0-9][0-9])[0-9]{12,15}|3[47][0-9]{13}|3(?:0[0-5]|[68][0-9])[0-9]{11}|(?:2131|1800|35\d{3})\d{11}|6[27][0-9]{14}|^(81[0-9]{14,17}))$/;
 /* eslint-enable max-len */
 
 export default function isCreditCard(str) {

test/validators.js

@@ -4575,6 +4575,8 @@ describe('Validators', () => {
         '2718760626256570',
         '6765780016990268',
         '4716989580001715211',
+        '8171999927660000',
+        '8171999900000000021',
       ],
       invalid: [
         'foo',