Julia app icon is too dark when using macOS Mojave's Dark Mode?

[cormullion]

On macOS using Dark Mode (Mojave), the Julia app's icons are very dark, quite a lot darker than everywhere else. This appears to be because the icons themselves are slightly transparent, not just the surrounding ('white') background:

True, the effect isn't displeasing, but the inconsistency may be a minor problem.

In the Finder the Julia app's icons are transparent, unlike, say, the icons of apps such as Keynote:

Apple's guidelines are here; I think they say that transparency should define shapes, rather than be used by the shapes themselves...

Edit: I worked out how to modify the icons and changed my local copy of Julia v0.6 (oh, the memories) to see what it looked like.