hardcoded post type in URLs

[paulgibbs]

https://wordpress.org/support/topic/hard-coded-post-type-name

` Hi Paul, thanks for the great plugin! I noticed that the post type name is hardcoded in the $parent_slug param of add_submenu_page() (cf. the "Users" and "Supported Plugins" submenus):

'edit.php?post_type=achievement'

Should be:

'edit.php?post_type=' . dpa_get_achievement_post_type() `