Most of the time, when you license something under GPLv3, you explicitly allow for later versions of the GPL. The "either version 3 of the License, or (at your option) any later version." part was famously removed in the Linux kernel.

This clause is a bit dangerous -- if a bad actor gets control of the FSF and manages to release an official GPL version that is completely bonkers, all current GPL-or-later software can be distributed under that license.

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.