meson: remove Windows subsystem version, it is 6.0 by default

meson.build

@@ -1807,7 +1807,7 @@ if get_option('cplayer')
     install_data('etc/mpv-symbolic.svg', install_dir: join_paths(hicolor_dir, 'symbolic', 'apps'))
 
     mpv = executable('mpv', main_fn_source, objects: libmpv.extract_all_objects(recursive: true), dependencies: dependencies,
-                     win_subsystem: 'windows,6.0', install: true)
+                     win_subsystem: 'windows', install: true)
 
     # Older meson versions generate this in the player subdirectory.
     if win32 and meson.version().version_compare('>= 1.3.0')