Allow to run bake {--list-targets, --list-vars} without having a docker daemon / builder instance available (similar to --print)

[neumantm]

Description

buildx bake already supports running with --print even if there is no docker daemon / builder instance available.

This exception is handled here:

buildx/commands/bake.go

Line 119 in 2bdf451

if url != "" || !in.printOnly {

I think it would be great if the same would apply to --list-targets and --list-vars.

I assume this is easy to add by just changing the above-mentioned condition as I assume the logic for these flags doesn't actually needs a builder and the function returns after processing either of these flags:

buildx/commands/bake.go

Lines 188 to 192 in 2bdf451

	if in.listTargets {
	return printTargetList(dockerCli.Out(), cfg)
	} else if in.listVars {
	return printVars(dockerCli.Out(), pm.AllVariables)
	}

I would be open to create a PR, if there is no argument against this.

[crazy-max]

Yes sounds good to me, feel free to open a PR, thanks!