Fly.io logo looks bad on dark background

[babakfp]

https://gleam.run/news/v0.25-introducing-use-expressions/

I'm not sure if this is that important or not. I randomly clicked on a link and saw this. It doesn't look good 🤷‍♂️

[lpil]

Ah yes. Let's use one of the inverted logos here: https://fly.io/docs/about/brand/