Failing to install danger-swift via HomeBrew

Failing to resolve dependencies.
What can I do?
Is this due to my local environment?

$ brew install danger/tap/danger-swift
==> Installing danger-swift from danger/tap
==> Downloading https://github.com/danger/danger-swift/archive/0.4.0.tar.gz
Already downloaded: /Users/hiragram/Library/Caches/Homebrew/danger-swift-0.4.0.tar.gz
==> make install PREFIX=/usr/local/Cellar/danger-swift/0.4.0
Last 15 lines from /Users/hiragram/Library/Logs/Homebrew/danger-swift/01.make:
swift package clean
swift build --disable-sandbox -c release --static-swift-stdlib
error: dependency graph is unresolvable; found these conflicting requirements:

Dependencies:
    https://github.com/JohnSundell/Marathon.git @ 3.0.0..<4.0.0
error: product dependency 'MarathonCore' not found
Fetching https://github.com/JohnSundell/Marathon.git
Fetching https://github.com/JohnSundell/Require.git
Fetching https://github.com/JohnSundell/ShellOut.git
Fetching https://github.com/JohnSundell/Wrap.git
Fetching https://github.com/JohnSundell/Files.git
Fetching https://github.com/JohnSundell/Releases.git
Fetching https://github.com/JohnSundell/Unbox.git
make: *** [build] Error 1

If reporting this issue please do so at (not Homebrew/brew or Homebrew/core):
https://github.com/danger/homebrew-tap/issues

Start by reproducing brew install danger/tap/danger-swift and reviewing the reported Swift package dependency-resolution errors. The issue mentions the downloaded 0.4.0 archive, the Homebrew install command, and dependencies including Marathon; done means the package installs without the reported conflict.