[runx] Add support for github token, implement resolve

[mikeland73]

Summary

This PR does a few things:

• Adds support for github token. This prevents rate-limiting when getting releases.json
• Adds resolve to API. This will allow devbox to validate packages exist and resolve versions in order to use lockfile.

@gcurtis I'm copying the devbox structure for the public interface (RunX interface) but was curious if you would do it differently. Specifically, we could remove the public interface and rename impl to just be runx and use a struct:

runx.New(runx.Opts{
  GithubAPIToken: "",
}).Install(...)

thoughts?

How was it tested?

RUNX_GITHUB_API_TOKEN=<token> runx +jetpack-io/envsec envsec
RUNX_GITHUB_API_TOKEN=<token> pkg resolve jetpack-io/envsec@latest
RUNX_GITHUB_API_TOKEN=<token> pkg resolve jetpack-io/envsec@v0.0.3

[gcurtis]

Looks good to me! I think we should eschew the interface and just use a struct. The impl pattern in Devbox feels a bit awkward and led to a giant interface.

[gcurtis]

My preference would be to put this struct directly in the runx package and remove the interface. Because the GitHub API token is optional, I'd also remove runopt in favor of setting the GithubAPIToken field directly. For example:

var r runx.Runx
// -- or --
// r := runx.RunX {
//     GithubAPIToken: "token",
// }
r.Run(ctx, "golangci-lint", "run")

[gcurtis]

The ~ won't expand if the path is used outside a shell. You probably want:

Suggested change

	cacheDir = "~/.cache"
	cacheDir = os.Expandenv("$HOME/.cache")

[mikeland73]

os.UserCacheDir() usually only errors if $HOME is empty. Will return error instead .