v5.0.0
Remove reciprocal_sub_requested
param, add_migration_complete_event_subscriber
function
reciprocal_sub_requested
is not really needed. the calling contract can just add the subscriber itself.
add_migration_complete_event_subscriber
is a new helper function to allow a contract to easily do this
rename:
NOTIFY_ON_MIGRATION_COMPLETE
-> MIGRATION_COMPLETE_EVENT_SUBSCRIBERS
REMAINING_NOTIFY_ON_MIGRATION_COMPLETE_SLOTS
-> REMAINING_MIGRATION_COMPLETE_EVENT_SUB_SLOTS