Also now that I'm playing with the icon, I think it'll be good to have a little bit of shadow/gradient to match other mac icons:
<img width="512" alt="geany-macos-icon" src="https://user-images.githubusercontent.com/2157285/140708240-e878246c-117a-407b-a97a-d00500a39b7b.png">
The new version vs the previous one:
<img width="438" alt="Screen Shot 1400-08-17 at 11 55 25" src="https://user-images.githubusercontent.com/2157285/140708163-91af1811-7be4-455f-bb5e-6ebf0ec25bb0.png">