Apple M1: Update AutoUpdate PlatformID

This will update the auto update Platform ID to macos-universal. This will
cause the auto updater to download universal builds as updates for all Mac OS
builds. Including previous single architecture builds.

Author: skylersaleh

Source/Core/UICommon/AutoUpdate.cpp

@@ -140,7 +140,7 @@ static std::string GetPlatformID()
 #if defined _WIN32
   return "win";
 #elif defined __APPLE__
-  return "macos";
+  return "macos-universal";
 #else
   return "unknown";
 #endif