How about installing/updating packages directly with juliaup?

[suxpert]

We have juliaup self up for updating juliaup, we also have juliaup up for updating julia, so how about another command juliaup pkg up for updating packages?

And perhaps more functions of the subcommand juliaup pkg, e.g., add, list, build..., just like in the pkg REPL. We may use the +lts syntax to specify which environment (or -n as in conda).

Then juliaup would be more closed to conda/mamba etc.