If that portion was antiquated then there would have been a reason for an amendment, not just ignoring the law. So simple even you should understand.
There's isn't any need to amend it for that. The actual text, "The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States," works just fine.
Really, show me where a period appears in Article 1, Section 8, which would make any part of it stand alone. Go ahead, I'll be happy to wait.