[macOS] Update icon for macOS Big Sur?

Is your feature request related to a problem? Please describe.
N/A

Describe the solution you'd like
Suggestion to update the icon of the macOS version of AltServer to match the new macOS Big Sur icon style?
Proposed new icon: https://github.com/elrumo/macOS-Big-Sur-icons-replacements/raw/master/icons/AltServer.icns

The icon linked above has a different license, so I don't know if it would work to directly use that icon. However, if you could consider making your own icon if you need to, using the linked icon as an idea, that would probably work better in that case...

[mattpilott]

Submitted a pull request for this #944

[lonkelle]

Thanks @mattpilott - it looks good to me. I'll close this out when Riley merges the change.