fix: bump app version to 1.6.3 since it's no longer a preview

package.json

@@ -2,7 +2,7 @@
   "name": "freedom-loader",
   "desktopName": "com.masteracnolo.freedomloader",
   "productName": "Freedom Loader",
-  "version": "1.6.3-preview",
+  "version": "1.6.3",
   "author": "MasterAcnolo <MasterAcnolo@users.noreply.github.com>",
   "description": "Free and open-source GUI for yt-dlp — download video and audio from hundreds of platforms",
   "homepage": "https://masteracnolo.github.io/Freedom-Loader-Site/",