That's one meaning of major version number. The original meaning is simply a release that is significantly different from the previous one. It's also possible to maintain more than one version number: a marketing version and an internal version (Windows did this famously where Windows 7 is actually version 6.1, Windows 8 is 6.2). Then there's a convention where the major version is the year number and it simply increases on Jan 1st, etc.

I have no knowledge of which convention Vite uses.