Use mirrors for downloading Zig (and ZLS?) tarballs

[Vexu]

Similar to https://github.com/mlugg/setup-zig this extension should also support using mirrors for downloading Zig tarballs.

I'd prefer updating the mirror list to not require updating the extension.

[Techatrix]

It shouldn't be too difficult to implement this on top of #230. I anticipated that mirrors could be added to this extension so I tried to plan ahead by adding minisign verification as an example.

I'd prefer updating the mirror list to not require updating the extension.

Does this mean that the mirror list is supposed to be configurable by the user?

[Vexu]

It shouldn't be too difficult to implement this on top of #230. I anticipated that mirrors could be added to this extension so I tried to plan ahead by adding minisign verification as an example.

I suspected that to be the case, good to get confirmation.

I'd prefer updating the mirror list to not require updating the extension.

Does this mean that the mirror list is supposed to be configurable by the user?

It doesn't have to be but that does seems like something someone could want. I was thinking there could be a mirror list hosted somewhere (maybe ziglang.org/download/mirrors.json) that the extension could check regularly.