Fix: `INVALID` userError handling

[pano9000]

Hi,

I noticed today, that the VIES service actually differentiates between INVALID and INVALID_INPUT userError messages:

• INVALID is returned, when you provide a valid country code, but the number is invalid
• INVALID_INPUT is returned, when the country code you provide is not valid

in both cases, it should be fine to say that the VAT Check returned "false" – however in the current version, vies-checker will currently throw an error, when you run e.g. await isValid('ES', 'ABC123456') (valid country + invalid vat no -> which would return INVALID as userError value).

To fix this, I've adapted the list of "handled" userErrors accordingly.

I also updated the tests accordingly as well, to now test all 3 cases.

Let me know, if there are any questions.

Kind regards,

[itaibo]

I published a minor version with these changes. Thank you 😊