chore: bump version to 0.8.0

Voice messages, offline queue, delivery receipts, group call scaling,
recovery code, push notifications scaffolding, admin panel, search v2,
focus-flicker fix.

apps/desktop/src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "ChatApp",
-  "version": "0.7.1",
+  "version": "0.8.0",
   "identifier": "com.meinname.chatapp",
   "build": {
     "beforeDevCommand": "pnpm vite:dev",