Support dev versions of Zig

[ZackeryRSmith]

Is your feature request related to a problem? Please describe.
I would like to use ZVM on projects that use Mach which runs off nominated Zig versions. These versions are almost always development versions which as of my knowledge ZVM can't actually download.

Describe the solution you'd like
Being allowed to install dev versions of Zig, even if it's only the nominated ones.

Describe alternatives you've considered
Being allowed to put my own zig binary into some directory and have ZVM work with it.

[ZackeryRSmith]

Ah nevermind, I solved my problem by looking at #45 (comment)

This really should be clarified, or maybe adding a command for listing/searching for zig versions you can install

[tristanisham]

There are commands,zvm ls -alland zvm vmu. It is also mentioned in the README and on the website.

Based on what we currently have, how could the documentation be clearer to communicate these features?

[ZackeryRSmith]

zvm ls is said to list all the currently installed zig versions. It doesn't mention at all in the help menu about this. I think a simple change adding that into the help menu would be super useful

Yes this is in the README, sorry I missed that...

[tristanisham]

I've updated the help menu copy and added more info to the readme. Thanks again for using ZVM. I hope it's been good to you otherwise.

https://github.com/tristanisham/zvm/releases/tag/v0.7.2