Advanced Custom Fields Pro 6.4.0.1

* Security - Setting a metabox callback for custom post types and taxonomies now requires being an admin, or super admin for multisite installs
* Security - Field specific ACF nonces are now prefixed, resolving an issue where third party nonces could be treated as valid for AJAX calls
* Enhancement - A new “Close and Add Field” option is now available when editing a field group, inserting a new field inline after the field being edited
* Enhancement - ACF and ACF PRO now share the same plugin updater for improved reliability and performance
* Fix - Exporting post types and taxonomies containing metabox callbacks now correctly exports the user defined callback

* Security - Editing an ACF Field in the Field Group editor can no longer execute a stored XSS vulnerability. Thanks to Duc Luong Tran (janlele91) from Viettel Cyber Security for the responsible disclosure
* Security - Post Type and Taxonomy metabox callbacks no longer have access to any superglobal values, hardening the original fix from 6.3.8 further
* Fix - ACF fields now correctly validate when used in the block editor and attached to the sidebar

* Security - ACF defined Post Type and Taxonomy metabox callbacks no longer have access to $_POST data. (Thanks to the Automattic Security Team for the disclosure)