fix: sync AUR workflow .SRCINFO with repo; bump to 2.0.2

The workflow was generating a hardcoded .SRCINFO that didn't include
python-fastapi or uvicorn, overwriting the correct file on every
release. Now it patches version/checksum in the existing .SRCINFO.

PKGBUILD

@@ -1,7 +1,7 @@
 # Maintainer: Sean Doran <sdoran35@gmail.com>
 # AUR updates are automated via GitHub Actions on version tag push
 pkgname=turn-up-arch
-pkgver=2.0.1
+pkgver=2.0.2
 pkgrel=1
 pkgdesc="USB serial knob/button mixer daemon for PipeWire/PulseAudio on Linux"
 arch=('any')