Win32: use ShellExecuteW instead of ShellExecuteA in the update code

Fixes #3355

src/misc/update.c

@@ -739,7 +739,9 @@ static void* update_DownloadReal( vlc_object_t *p_this )
 
     if(answer == 1)
     {
-        answer = ShellExecuteA( NULL, "open", psz_destfile, NULL, NULL, SW_SHOW);
+        wchar_t psz_wdestfile[MAX_PATH];
+        MultiByteToWideChar( CP_UTF8, 0, psz_destfile, -1, psz_wdestfile, MAX_PATH );
+        answer = ShellExecuteW( NULL, L"open", psz_wdestfile, NULL, NULL, SW_SHOW);
         if(answer > 32)
             libvlc_Quit(p_this->p_libvlc);
     }