Validates if the input is ISIN.
Valid values:
validator.isin().validate('AU0000XVGZA3');
validator.isin().validate('DE000BAY0017');
validator.isin().validate('BE0003796134');
validator.isin().validate('SG1G55870362');
Invalid values:
validator.isin().validate('DE000BAY0018');
validator.isin().validate('PLLWBGD00019');
validator.isin().validate('foo');
validator.isin().validate('5398228707871528');