Describe the bug

There are two sunshine packages on AUR, manually maintained.

• https://aur.archlinux.org/packages/sunshine
• https://aur.archlinux.org/packages/sunshine-git

Expected behavior

• Build the AUR package on PRs into nightly and master.
• Automate the AUR package update when a push is made into master branch.
  • Hopefully pkgver can be automated easily (we already get version automatically from the CHANGELOG file)
    • https://aur.archlinux.org/cgit/aur.git/tree/PKGBUILD?h=sunshine#n4
    • https://aur.archlinux.org/cgit/aur.git/tree/PKGBUILD?h=sunshine-git#n5
  • url also should be updated to match this repo
• This file needs to be updated (https://github.com/SunshineStream/Sunshine/blob/nightly/.github/workflows/CI.yml)