Custom field for CMB2.

Adds the ability to add custom fields to the new WooCommerce HPOS orders page.

Follow the example in example-field-setup.php for a demonstration. The example assumes you have both CMB2 and this extension in your mu-plugins directory. If you're using CMB2 installed as a plugin, you can remove the require_once line.

You can retrieve the meta data using the following:

$test_text_value = wc_get_order( $order_id )->get_meta( 'yourprefix_woo_orders_text', true, 'edit' );

• Bugfix: Gate the cmb2_override_meta_* filters to the orders object type so they no longer run for unrelated CMB2 fields (posts, pages, users, etc.), which caused a fatal Call to undefined function wc_get_order() when WooCommerce was inactive.
• Guard wc_get_order() with function_exists() since this loads as an mu-plugin regardless of whether WooCommerce is active.

• Release