Does not support distributions lacking a root directory

I am attempting to use GrabTool to install a GitHub distribution that does not contain a root directory within the ZIP.

org.ysb33r.grolifant.api.errors.DistributionFailedException: Grabatool: structurizr 'https://github.com/structurizr/cli/releases/download/v1.12.0/structurizr-cli-1.12.0.zip contains too many directories. Expected to find exactly 1 directory.
        at org.ysb33r.grolifant.api.v4.AbstractDistributionInstaller.getAndVerifyDistributionRoot(AbstractDistributionInstaller.groovy:292)
        at org.ysb33r.grolifant.api.v4.AbstractDistributionInstaller$1.verify(AbstractDistributionInstaller.groovy:160)

Example script to reproduce (Kotlin syntax):

import java.net.URI
import org.ysb33r.gradle.grabatool.GrabaToolEntryPointDescriptor
import org.ysb33r.gradle.grabatool.GrabaToolUriDescriptor

plugins {
    id ("org.ysb33r.grabatool")  version "0.4.1"
}

grabatool {
    tool("structurizr") {
        uri { cfg: GrabaToolUriDescriptor ->
            URI("https://github.com/structurizr/cli/releases/download/v${cfg.version}/structurizr-cli-${cfg.version}.zip")
        }

        entrypoint { ep: GrabaToolEntryPointDescriptor ->
            val ext = if (ep.os.isWindows()) {
                ".exe" 
            } else { 
                ".sh"
            }

            File(ep.distributionRoot, "structurizr${ext}")
        }
    }
}

val structVersion = "1.12.0"

println(grabatool.get("structurizr").version(structVersion).entrypoint("foo"))