Update to most updated version of a Major

[IncognitaDev]

I'm working in a project that does not support Deno 2.0, but in some projects the Deno 2.0 is required, so I have to change the version sometimes. The upgrade command requires a full version to update, its require that I remember the last version of the 1 major ever. I was think about to allow the only major as argument

today: deno upgrade 1.46.3 suggestion: deno upgrade 1

In this way we can get the last version of the major of the argument and install it.

If you think its ok, I want to make this contribution.