No, you can’t change the capability settings in the wp-config.php like Contact Form 7. Instead try adding this code to your theme’s functions.php:
remove_filter( 'map_meta_cap', 'flamingo_map_meta_cap' );
add_filter( 'map_meta_cap', 'mycustom_flamingo_map_meta_cap', 9, 4 );
function mycustom_flamingo_map_meta_cap( $caps, $cap, $user_id, $args ) {
? ?$meta_caps = array(
? ? ? ?'flamingo_edit_contacts' => 'publish_posts',
? ? ? ?'flamingo_edit_contact' => 'publish_posts',
? ? ? ?'flamingo_delete_contact' => 'publish_posts',
? ? ? ?'flamingo_edit_inbound_messages' => 'publish_posts',
? ? ? ?'flamingo_delete_inbound_message' => 'publish_posts',
? ? ? ?'flamingo_delete_inbound_messages' => 'publish_posts',
? ? ? ?'flamingo_spam_inbound_message' => 'publish_posts',
? ? ? ?'flamingo_unspam_inbound_message' => 'publish_posts' );
? ?$caps = array_diff( $caps, array_keys( $meta_caps ) );
? ?if ( isset( $meta_caps[$cap] ) )
? ? ? ?$caps[] = $meta_caps[$cap];
? ?return $caps;
}